feat: add category management UI and relocate navbar controls to quick-actions modal

client/src/components/layout/LanguageSwitcher.tsx

@@ -1,5 +1,6 @@
 import { useTranslation } from 'react-i18next';
 import { FormControl, InputLabel, MenuItem, Select } from '@mui/material';
+import type { SelectProps } from '@mui/material/Select';
 import { SUPPORTED_LANGUAGES, type SupportedLanguage } from '../../i18n';
 
 const LABEL_LOOKUP: Record<SupportedLanguage, string> = {
@@ -7,14 +8,19 @@ const LABEL_LOOKUP: Record<SupportedLanguage, string> = {
   en: 'language.en'
 };
 
-export function LanguageSwitcher() {
+interface LanguageSwitcherProps {
+  selectProps?: Partial<SelectProps<SupportedLanguage>>;
+  fullWidth?: boolean;
+}
+
+export function LanguageSwitcher({ selectProps, fullWidth = false }: LanguageSwitcherProps = {}) {
   const { t, i18n } = useTranslation();
 
   const currentLanguage =
     SUPPORTED_LANGUAGES.find((language) => i18n.language.startsWith(language)) ?? 'zh-Hant';
 
   return (
-    <FormControl size="small">
+    <FormControl size="small" fullWidth={fullWidth} sx={{ minWidth: fullWidth ? undefined : 140 }}>
       <InputLabel id="language-switcher-label">{t('language.label')}</InputLabel>
       <Select
         labelId="language-switcher-label"
@@ -24,7 +30,7 @@ export function LanguageSwitcher() {
           const selected = event.target.value as SupportedLanguage;
           void i18n.changeLanguage(selected);
         }}
-        sx={{ minWidth: 140 }}
+        {...selectProps}
       >
         {SUPPORTED_LANGUAGES.map((language) => (
           <MenuItem key={language} value={language}>

client/src/components/layout/PrimaryLayout.tsx

@@ -6,16 +6,17 @@ import {
   Divider,
   Drawer,
   IconButton,
-  Link,
   Stack,
   Toolbar,
+  Tooltip,
   Typography,
   useMediaQuery
 } from '@mui/material';
 import MenuIcon from '@mui/icons-material/Menu';
 import ChevronLeftIcon from '@mui/icons-material/ChevronLeft';
 import { useTheme } from '@mui/material/styles';
-import { LanguageSwitcher } from './LanguageSwitcher';
+import MoreVertIcon from '@mui/icons-material/MoreVert';
+import { NavControlsDialog } from '../overlay/NavControlsDialog';
 
 interface PrimaryLayoutProps {
   sidebar: ReactNode;
@@ -30,6 +31,7 @@ export function PrimaryLayout({ sidebar, content, onSidebarToggle }: PrimaryLayo
   const theme = useTheme();
   const isDesktop = useMediaQuery(theme.breakpoints.up('lg'));
   const [isSidebarOpen, setIsSidebarOpen] = useState(isDesktop);
+  const [isNavControlsOpen, setIsNavControlsOpen] = useState(false);
 
   useEffect(() => {
     setIsSidebarOpen(isDesktop);
@@ -67,16 +69,12 @@ export function PrimaryLayout({ sidebar, content, onSidebarToggle }: PrimaryLayo
               </Typography>
             </Box>
           </Stack>
-          <Stack direction="row" spacing={2} alignItems="center">
+          <Stack direction="row" spacing={1} alignItems="center">
-            <Stack direction="row" spacing={2} sx={{ display: { xs: 'none', sm: 'flex' } }}>
+            <Tooltip title={t('nav.openControls')}>
-              <Link href="https://www.openstreetmap.org/" target="_blank" rel="noreferrer" underline="hover" color="text.secondary">
+              <IconButton color="primary" onClick={() => setIsNavControlsOpen(true)}>
-                {t('nav.openStreetMap')}
+                <MoreVertIcon />
-              </Link>
+              </IconButton>
-              <Link href="https://react-leaflet.js.org/" target="_blank" rel="noreferrer" underline="hover" color="text.secondary">
+            </Tooltip>
-                {t('nav.reactLeaflet')}
-              </Link>
-            </Stack>
-            <LanguageSwitcher />
           </Stack>
         </Toolbar>
       </AppBar>
@@ -116,6 +114,7 @@ export function PrimaryLayout({ sidebar, content, onSidebarToggle }: PrimaryLayo
 
         <Box component="main" sx={{ flexGrow: 1, minHeight: 0 }}>{content}</Box>
       </Box>
+      <NavControlsDialog open={isNavControlsOpen} onClose={() => setIsNavControlsOpen(false)} />
     </Box>
   );
 }

client/src/components/layout/VisitSidebar.tsx

@@ -3,6 +3,7 @@ import { Button, Card, CardContent, Stack, Typography } from '@mui/material';
 import AddIcon from '@mui/icons-material/Add';
 import { VisitList } from '../../features/visits/components/VisitList';
 import { VisitSummary } from '../../features/visits/components/VisitSummary';
+import { VisitCategorySelector } from '../../features/categories/components/VisitCategorySelector';
 import { useVisitModalStore } from '../../state/useVisitModalStore';
 
 export function VisitSidebar() {
@@ -31,6 +32,8 @@ export function VisitSidebar() {
         </Button>
       </Stack>
 
+      <VisitCategorySelector />
+
       <VisitSummary />
 
       <Card sx={{ flex: 1, overflow: 'hidden', display: 'flex' }}>

client/src/components/overlay/NavControlsDialog.tsx

@@ -0,0 +1,72 @@
+import { Dialog, DialogActions, DialogContent, DialogTitle, Stack, Button, Typography } from '@mui/material';
+import LaunchIcon from '@mui/icons-material/Launch';
+import { useTranslation } from 'react-i18next';
+import { LanguageSwitcher } from '../layout/LanguageSwitcher';
+import { VisitCategoryNavSelect } from '../../features/categories/components/VisitCategoryNavSelect';
+
+interface NavControlsDialogProps {
+  open: boolean;
+  onClose: () => void;
+}
+
+export function NavControlsDialog({ open, onClose }: NavControlsDialogProps) {
+  const { t } = useTranslation();
+
+  return (
+    <Dialog open={open} onClose={onClose} fullWidth maxWidth="xs">
+      <DialogTitle>{t('nav.controls')}</DialogTitle>
+      <DialogContent dividers>
+        <Stack spacing={3}>
+          <Typography variant="body2" color="text.secondary">
+            {t('nav.controlsDescription')}
+          </Typography>
+
+          <Stack spacing={1.5}>
+            <Typography variant="subtitle2" color="text.secondary">
+              {t('categories.selectLabel')}
+            </Typography>
+            <VisitCategoryNavSelect fullWidth />
+          </Stack>
+
+          <Stack spacing={1.5}>
+            <Typography variant="subtitle2" color="text.secondary">
+              {t('language.label')}
+            </Typography>
+            <LanguageSwitcher fullWidth />
+          </Stack>
+
+          <Stack spacing={1}>
+            <Typography variant="subtitle2" color="text.secondary">
+              {t('nav.links')}
+            </Typography>
+            <Stack spacing={1}>
+              <Button
+                variant="outlined"
+                endIcon={<LaunchIcon fontSize="small" />}
+                component="a"
+                href="https://www.openstreetmap.org/"
+                target="_blank"
+                rel="noreferrer"
+              >
+                {t('nav.openStreetMap')}
+              </Button>
+              <Button
+                variant="outlined"
+                endIcon={<LaunchIcon fontSize="small" />}
+                component="a"
+                href="https://react-leaflet.js.org/"
+                target="_blank"
+                rel="noreferrer"
+              >
+                {t('nav.reactLeaflet')}
+              </Button>
+            </Stack>
+          </Stack>
+        </Stack>
+      </DialogContent>
+      <DialogActions>
+        <Button onClick={onClose}>{t('nav.close')}</Button>
+      </DialogActions>
+    </Dialog>
+  );
+}

client/src/components/overlay/VisitModal.tsx

@@ -9,10 +9,12 @@ import {
 import CloseIcon from '@mui/icons-material/Close';
 import { useVisitModalStore } from '../../state/useVisitModalStore';
 import { VisitForm } from '../../features/visits/components/VisitForm';
+import { useVisitCategorySelectionStore } from '../../state/useVisitCategorySelectionStore';
 
 export function VisitModal() {
   const { isOpen, close, editingVisit, initialLocation } = useVisitModalStore();
   const { t } = useTranslation();
+  const selectedCategoryId = useVisitCategorySelectionStore((state) => state.selectedCategoryId);
 
   return (
     <Dialog open={isOpen} onClose={close} maxWidth="sm" fullWidth>
@@ -30,7 +32,13 @@ export function VisitModal() {
         </IconButton>
       </DialogTitle>
       <DialogContent dividers>
-        <VisitForm editingVisit={editingVisit} initialLocation={initialLocation} onCompleted={close} onCancel={close} />
+        <VisitForm
+          editingVisit={editingVisit}
+          initialLocation={initialLocation}
+          selectedCategoryId={selectedCategoryId}
+          onCompleted={close}
+          onCancel={close}
+        />
       </DialogContent>
     </Dialog>
   );

client/src/features/categories/components/VisitCategoryNavSelect.tsx

@@ -0,0 +1,83 @@
+import { useEffect, useMemo } from 'react';
+import { useTranslation } from 'react-i18next';
+import {
+  FormControl,
+  InputLabel,
+  MenuItem,
+  Select,
+  type SelectChangeEvent
+} from '@mui/material';
+import type { SxProps, Theme } from '@mui/material/styles';
+import {
+  UNCATEGORIZED_CATEGORY_ID,
+  useVisitCategorySelectionStore
+} from '../../../state/useVisitCategorySelectionStore';
+import { useVisitCategoriesQuery } from '../hooks/useVisitCategoryQueries';
+
+const ALL_OPTION_VALUE = '__all__';
+
+interface VisitCategoryNavSelectProps {
+  fullWidth?: boolean;
+  sx?: SxProps<Theme>;
+}
+
+export function VisitCategoryNavSelect({ fullWidth = false, sx }: VisitCategoryNavSelectProps) {
+  const { t } = useTranslation();
+  const { data: categories = [], isLoading } = useVisitCategoriesQuery();
+  const selectedCategoryId = useVisitCategorySelectionStore((state) => state.selectedCategoryId);
+  const setSelectedCategoryId = useVisitCategorySelectionStore((state) => state.setSelectedCategoryId);
+
+  const selectValue = selectedCategoryId ?? ALL_OPTION_VALUE;
+
+  const options = useMemo(() => {
+    return [
+      { value: ALL_OPTION_VALUE, label: t('categories.all') },
+      { value: UNCATEGORIZED_CATEGORY_ID, label: t('categories.uncategorized') },
+      ...categories.map((category) => ({ value: category.id, label: category.name }))
+    ];
+  }, [categories, t]);
+
+  const handleChange = (event: SelectChangeEvent<string>) => {
+    const value = event.target.value;
+    if (value === ALL_OPTION_VALUE) {
+      setSelectedCategoryId(null);
+      return;
+    }
+
+    setSelectedCategoryId(value);
+  };
+
+  useEffect(() => {
+    if (!selectedCategoryId || selectedCategoryId === UNCATEGORIZED_CATEGORY_ID) {
+      return;
+    }
+
+    const exists = categories.some((category) => category.id === selectedCategoryId);
+    if (!exists) {
+      setSelectedCategoryId(null);
+    }
+  }, [categories, selectedCategoryId, setSelectedCategoryId]);
+
+  return (
+    <FormControl
+      size="small"
+      fullWidth={fullWidth}
+      sx={{ minWidth: fullWidth ? undefined : 180, ...sx }}
+      disabled={isLoading}
+    >
+      <InputLabel id="visit-category-nav-select-label">{t('categories.selectLabel')}</InputLabel>
+      <Select
+        labelId="visit-category-nav-select-label"
+        label={t('categories.selectLabel')}
+        value={selectValue}
+        onChange={handleChange}
+      >
+        {options.map((option) => (
+          <MenuItem key={option.value} value={option.value}>
+            {option.label}
+          </MenuItem>
+        ))}
+      </Select>
+    </FormControl>
+  );
+}

client/src/features/categories/components/VisitCategorySelector.tsx

@@ -0,0 +1,306 @@
+import { type FormEvent, useEffect, useMemo, useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import {
+  Box,
+  Button,
+  Card,
+  CardContent,
+  Chip,
+  CircularProgress,
+  Dialog,
+  DialogActions,
+  DialogContent,
+  DialogTitle,
+  IconButton,
+  Stack,
+  TextField,
+  Typography
+} from '@mui/material';
+import AddIcon from '@mui/icons-material/Add';
+import {
+  useCreateVisitCategoryMutation,
+  useDeleteVisitCategoryMutation,
+  useUpdateVisitCategoryMutation,
+  useVisitCategoriesQuery
+} from '../hooks/useVisitCategoryQueries';
+import { useVisitCategorySelectionStore, UNCATEGORIZED_CATEGORY_ID } from '../../../state/useVisitCategorySelectionStore';
+import EditIcon from '@mui/icons-material/Edit';
+import DeleteIcon from '@mui/icons-material/Delete';
+import type { VisitCategory } from '../types';
+
+export function VisitCategorySelector() {
+  const { t } = useTranslation();
+  const { data: categories = [], isLoading } = useVisitCategoriesQuery();
+  const createCategoryMutation = useCreateVisitCategoryMutation();
+  const updateCategoryMutation = useUpdateVisitCategoryMutation();
+  const deleteCategoryMutation = useDeleteVisitCategoryMutation();
+  const selectedCategoryId = useVisitCategorySelectionStore((state) => state.selectedCategoryId);
+  const setSelectedCategoryId = useVisitCategorySelectionStore((state) => state.setSelectedCategoryId);
+  const [newCategoryName, setNewCategoryName] = useState('');
+  const [editingCategory, setEditingCategory] = useState<VisitCategory | null>(null);
+  const [renameValue, setRenameValue] = useState('');
+  const [categoryPendingDeletion, setCategoryPendingDeletion] = useState<VisitCategory | null>(null);
+
+  const chips = useMemo(() => {
+    const chipItems = [
+      {
+        id: null as string | null,
+        label: t('categories.all'),
+        isSelected: selectedCategoryId === null
+      },
+      {
+        id: UNCATEGORIZED_CATEGORY_ID,
+        label: t('categories.uncategorized'),
+        isSelected: selectedCategoryId === UNCATEGORIZED_CATEGORY_ID
+      }
+    ];
+
+    return [
+      ...chipItems,
+      ...categories.map((category) => ({
+        id: category.id,
+        label: category.name,
+        isSelected: selectedCategoryId === category.id
+      }))
+    ];
+  }, [categories, selectedCategoryId, t]);
+
+  useEffect(() => {
+    if (!selectedCategoryId) {
+      return;
+    }
+
+    if (selectedCategoryId === UNCATEGORIZED_CATEGORY_ID) {
+      return;
+    }
+
+    const exists = categories.some((category) => category.id === selectedCategoryId);
+    if (!exists) {
+      setSelectedCategoryId(null);
+    }
+  }, [categories, selectedCategoryId, setSelectedCategoryId]);
+
+  useEffect(() => {
+    if (editingCategory) {
+      setRenameValue(editingCategory.name);
+    } else {
+      setRenameValue('');
+    }
+  }, [editingCategory]);
+
+  async function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    const trimmed = newCategoryName.trim();
+    if (!trimmed) {
+      return;
+    }
+
+    try {
+      const category = await createCategoryMutation.mutateAsync({ name: trimmed });
+      setNewCategoryName('');
+      setSelectedCategoryId(category.id);
+    } catch (error) {
+      console.error(error);
+    }
+  }
+
+  function handleEdit(category: VisitCategory) {
+    setEditingCategory(category);
+  }
+
+  function handleRequestDelete(category: VisitCategory) {
+    setCategoryPendingDeletion(category);
+  }
+
+  async function handleRenameSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    if (!editingCategory) {
+      return;
+    }
+
+    const trimmed = renameValue.trim();
+    if (!trimmed) {
+      return;
+    }
+
+    if (trimmed === editingCategory.name) {
+      setEditingCategory(null);
+      return;
+    }
+
+    try {
+      await updateCategoryMutation.mutateAsync({ id: editingCategory.id, data: { name: trimmed } });
+      setEditingCategory(null);
+    } catch (error) {
+      console.error(error);
+    }
+  }
+
+  async function handleDeleteConfirm() {
+    if (!categoryPendingDeletion) {
+      return;
+    }
+
+    const categoryId = categoryPendingDeletion.id;
+
+    try {
+      await deleteCategoryMutation.mutateAsync(categoryId);
+      if (selectedCategoryId === categoryId) {
+        setSelectedCategoryId(null);
+      }
+      setCategoryPendingDeletion(null);
+    } catch (error) {
+      console.error(error);
+    }
+  }
+
+  const isCreating = createCategoryMutation.isPending;
+  const isRenaming = updateCategoryMutation.isPending;
+  const isDeleting = deleteCategoryMutation.isPending;
+
+  const handleCloseRenameDialog = () => {
+    if (isRenaming) {
+      return;
+    }
+    setEditingCategory(null);
+  };
+
+  const handleCloseDeleteDialog = () => {
+    if (isDeleting) {
+      return;
+    }
+    setCategoryPendingDeletion(null);
+  };
+
+  return (
+    <>
+      <Card variant="outlined">
+        <CardContent sx={{ py: 1.5, px: 2 }}>
+          <Stack spacing={1.5}>
+            <Typography variant="subtitle2" color="text.secondary">
+              {t('categories.title')}
+            </Typography>
+            <Stack direction="row" spacing={1} flexWrap="wrap" useFlexGap>
+              {chips.map((chip) => (
+                <Chip
+                  key={chip.id ?? 'all'}
+                  label={chip.label}
+                  color={chip.isSelected ? 'primary' : 'default'}
+                  variant={chip.isSelected ? 'filled' : 'outlined'}
+                  onClick={() => setSelectedCategoryId(chip.id)}
+                  disabled={isLoading && chip.id !== null && chip.id !== UNCATEGORIZED_CATEGORY_ID}
+                />
+              ))}
+              {isLoading ? <CircularProgress size={18} /> : null}
+            </Stack>
+            <Box component="form" onSubmit={handleSubmit} sx={{ display: 'flex', gap: 1 }}>
+              <TextField
+                value={newCategoryName}
+                onChange={(event) => setNewCategoryName(event.target.value)}
+                placeholder={t('categories.addPlaceholder')}
+                size="small"
+                fullWidth
+                disabled={isCreating}
+              />
+              <Button
+                type="submit"
+                variant="contained"
+                startIcon={<AddIcon />}
+                disabled={!newCategoryName.trim() || isCreating}
+              >
+                {t('categories.addButton')}
+              </Button>
+            </Box>
+            {categories.length ? (
+              <Stack spacing={1.5}>
+                <Typography variant="subtitle2" color="text.secondary">
+                  {t('categories.manage')}
+                </Typography>
+                <Stack spacing={1}>
+                  {categories.map((category) => (
+                    <Stack
+                      key={category.id}
+                      direction="row"
+                      alignItems="center"
+                      justifyContent="space-between"
+                      sx={{ border: 1, borderColor: 'divider', borderRadius: 1, px: 1, py: 0.75 }}
+                    >
+                      <Typography
+                        variant="body2"
+                        color="text.primary"
+                        sx={{ overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', pr: 1 }}
+                      >
+                        {category.name}
+                      </Typography>
+                      <Stack direction="row" spacing={0.5}>
+                        <IconButton
+                          size="small"
+                          onClick={() => handleEdit(category)}
+                          aria-label={t('categories.edit')}
+                          disabled={isRenaming || isDeleting}
+                        >
+                          <EditIcon fontSize="small" />
+                        </IconButton>
+                        <IconButton
+                          size="small"
+                          color="error"
+                          onClick={() => handleRequestDelete(category)}
+                          aria-label={t('categories.delete')}
+                          disabled={isRenaming || isDeleting}
+                        >
+                          <DeleteIcon fontSize="small" />
+                        </IconButton>
+                      </Stack>
+                    </Stack>
+                  ))}
+                </Stack>
+              </Stack>
+            ) : null}
+        </Stack>
+      </CardContent>
+      </Card>
+
+      <Dialog open={Boolean(editingCategory)} onClose={handleCloseRenameDialog} fullWidth maxWidth="xs">
+        <Box component="form" onSubmit={handleRenameSubmit}>
+          <DialogTitle>{t('categories.renameTitle')}</DialogTitle>
+          <DialogContent sx={{ pt: 1 }}>
+            <TextField
+              autoFocus
+              margin="dense"
+              fullWidth
+              value={renameValue}
+              onChange={(event) => setRenameValue(event.target.value)}
+              placeholder={t('categories.renamePlaceholder')}
+              disabled={isRenaming}
+            />
+          </DialogContent>
+          <DialogActions>
+            <Button onClick={handleCloseRenameDialog} disabled={isRenaming}>
+              {t('nav.close')}
+            </Button>
+            <Button type="submit" variant="contained" disabled={isRenaming || !renameValue.trim()}>
+              {t('categories.renameSubmit')}
+            </Button>
+          </DialogActions>
+        </Box>
+      </Dialog>
+
+      <Dialog open={Boolean(categoryPendingDeletion)} onClose={handleCloseDeleteDialog} fullWidth maxWidth="xs">
+        <DialogTitle>{t('categories.deleteTitle')}</DialogTitle>
+        <DialogContent>
+          <Typography variant="body2" color="text.secondary">
+            {t('categories.deleteMessage', { name: categoryPendingDeletion?.name ?? '' })}
+          </Typography>
+        </DialogContent>
+        <DialogActions>
+          <Button onClick={handleCloseDeleteDialog} disabled={isDeleting}>
+            {t('nav.close')}
+          </Button>
+          <Button onClick={handleDeleteConfirm} color="error" variant="contained" disabled={isDeleting}>
+            {t('categories.deleteConfirm')}
+          </Button>
+        </DialogActions>
+      </Dialog>
+    </>
+  );
+}

client/src/features/categories/hooks/useVisitCategoryQueries.ts

@@ -0,0 +1,54 @@
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import type {
+  VisitCategory,
+  VisitCategoryCreateInput,
+  VisitCategoryId,
+  VisitCategoryUpdateInput
+} from '../types';
+import { useVisitCategoryRepository } from '../../visits/context/VisitProvider';
+
+const VISIT_CATEGORIES_QUERY_KEY = ['visitCategories'];
+
+export function useVisitCategoriesQuery() {
+  const repository = useVisitCategoryRepository();
+  return useQuery({
+    queryKey: VISIT_CATEGORIES_QUERY_KEY,
+    queryFn: () => repository.getAll()
+  });
+}
+
+export function useCreateVisitCategoryMutation() {
+  const repository = useVisitCategoryRepository();
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (input: VisitCategoryCreateInput) => repository.create(input),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: VISIT_CATEGORIES_QUERY_KEY });
+    }
+  });
+}
+
+export function useUpdateVisitCategoryMutation() {
+  const repository = useVisitCategoryRepository();
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: ({ id, data }: { id: VisitCategoryId; data: VisitCategoryUpdateInput }) =>
+      repository.update(id, data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: VISIT_CATEGORIES_QUERY_KEY });
+    }
+  });
+}
+
+export function useDeleteVisitCategoryMutation() {
+  const repository = useVisitCategoryRepository();
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (id: VisitCategoryId) => repository.remove(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: VISIT_CATEGORIES_QUERY_KEY });
+    }
+  });
+}
+
+export type VisitCategoryListData = VisitCategory[];

client/src/features/categories/storage/localVisitCategoryRepository.ts

@@ -0,0 +1,70 @@
+import { nanoid } from 'nanoid';
+import { loadFromStorage, saveToStorage } from '../../../lib/browserStorage';
+import type { VisitCategory, VisitCategoryRepository } from '../types';
+import { localVisitRepository } from '../../visits/storage/localVisitRepository';
+
+const STORAGE_KEY = 'traveling-around-the-world::visitCategories';
+
+function stamp(): string {
+  return new Date().toISOString();
+}
+
+function loadCategories(): VisitCategory[] {
+  return loadFromStorage<VisitCategory[]>(STORAGE_KEY, []);
+}
+
+function persistCategories(categories: VisitCategory[]): void {
+  saveToStorage(STORAGE_KEY, categories);
+}
+
+export const localVisitCategoryRepository: VisitCategoryRepository = {
+  async getAll() {
+    return loadCategories();
+  },
+  async getById(id) {
+    return loadCategories().find((category) => category.id === id);
+  },
+  async create(input) {
+    const categories = loadCategories();
+    const now = stamp();
+    const category: VisitCategory = {
+      id: nanoid(),
+      createdAt: now,
+      updatedAt: now,
+      name: input.name
+    };
+    persistCategories([category, ...categories]);
+    return category;
+  },
+  async update(id, input) {
+    const categories = loadCategories();
+    const idx = categories.findIndex((category) => category.id === id);
+    if (idx < 0) {
+      throw new Error(`Category with id ${id} not found`);
+    }
+    const updated: VisitCategory = {
+      ...categories[idx],
+      ...input,
+      updatedAt: stamp()
+    };
+    categories[idx] = updated;
+    persistCategories(categories);
+    return updated;
+  },
+  async remove(id) {
+    const categories = loadCategories().filter((category) => category.id !== id);
+    persistCategories(categories);
+    if (this.detachVisitsFromCategory) {
+      await this.detachVisitsFromCategory(id);
+    }
+  },
+  async detachVisitsFromCategory(categoryId) {
+    const visits = await localVisitRepository.getAll();
+    const updates = visits
+      .filter((visit) => visit.categoryId === categoryId)
+      .map((visit) => localVisitRepository.update(visit.id, { categoryId: undefined }));
+    await Promise.all(updates);
+  }
+};
+
+export type LocalVisitCategoryRepository = typeof localVisitCategoryRepository;

client/src/features/categories/types.ts

@@ -0,0 +1,25 @@
+export type VisitCategoryId = string;
+
+export interface VisitCategory {
+  id: VisitCategoryId;
+  name: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface VisitCategoryCreateInput {
+  name: string;
+}
+
+export interface VisitCategoryUpdateInput {
+  name: string;
+}
+
+export interface VisitCategoryRepository {
+  getAll(): Promise<VisitCategory[]>;
+  getById(id: VisitCategoryId): Promise<VisitCategory | undefined>;
+  create(input: VisitCategoryCreateInput): Promise<VisitCategory>;
+  update(id: VisitCategoryId, input: VisitCategoryUpdateInput): Promise<VisitCategory>;
+  remove(id: VisitCategoryId): Promise<void>;
+  detachVisitsFromCategory?(categoryId: VisitCategoryId): Promise<void>;
+}

client/src/features/visits/components/VisitForm.tsx

@@ -7,6 +7,7 @@ import {
   Box,
   Button,
   Grid,
+  MenuItem,
   Stack,
   TextField,
   Typography
@@ -15,6 +16,8 @@ import type { Visit, VisitCreateInput } from '../types';
 import { useCreateVisitMutation, useUpdateVisitMutation } from '../hooks/useVisitQueries';
 import { useTranslation } from 'react-i18next';
 import { reverseGeocode } from '../utils/geocoding';
+import { useVisitCategoriesQuery } from '../../categories/hooks/useVisitCategoryQueries';
+import { UNCATEGORIZED_CATEGORY_ID } from '../../../state/useVisitCategorySelectionStore';
 
 function getTodayDate(): string {
   const now = new Date();
@@ -30,6 +33,7 @@ const visitFormSchema = z
     start: z.string().min(1, 'validation.startDateRequired'),
     end: z.string().optional(),
     notes: z.string().optional(),
+    categoryId: z.string().optional(),
     lat: z.number(),
     lng: z.number()
   })
@@ -48,15 +52,29 @@ interface VisitFormProps {
   onCompleted?: () => void;
   onCancel?: () => void;
   initialLocation?: { lat: number; lng: number };
+  selectedCategoryId?: string | null;
 }
 
-export function VisitForm({ editingVisit, onCompleted, onCancel, initialLocation }: VisitFormProps) {
+export function VisitForm({
+  editingVisit,
+  onCompleted,
+  onCancel,
+  initialLocation,
+  selectedCategoryId
+}: VisitFormProps) {
   const { t } = useTranslation();
   const [isGeocoding, setIsGeocoding] = useState(false);
   const [geocodeFailed, setGeocodeFailed] = useState(false);
 
   const createMutation = useCreateVisitMutation();
   const updateMutation = useUpdateVisitMutation();
+  const { data: categories = [] } = useVisitCategoriesQuery();
+
+  const defaultCategoryId = editingVisit?.categoryId
+    ? editingVisit.categoryId
+    : selectedCategoryId && selectedCategoryId !== UNCATEGORIZED_CATEGORY_ID
+      ? selectedCategoryId
+      : '';
 
   const {
     register,
@@ -72,6 +90,7 @@ export function VisitForm({ editingVisit, onCompleted, onCancel, initialLocation
       start: editingVisit?.date.start ?? getTodayDate(),
       end: editingVisit?.date.end ?? '',
       notes: editingVisit?.notes ?? '',
+      categoryId: defaultCategoryId,
       lat: editingVisit?.location.lat ?? initialLocation?.lat ?? 0,
       lng: editingVisit?.location.lng ?? initialLocation?.lng ?? 0
     }
@@ -84,6 +103,25 @@ export function VisitForm({ editingVisit, onCompleted, onCancel, initialLocation
     }
   }, [initialLocation, editingVisit, setValue]);
 
+  useEffect(() => {
+    if (editingVisit) {
+      return;
+    }
+
+    if (!selectedCategoryId || selectedCategoryId === UNCATEGORIZED_CATEGORY_ID) {
+      setValue('categoryId', '', { shouldDirty: false });
+      return;
+    }
+
+    const exists = categories.some((category) => category.id === selectedCategoryId);
+    if (!exists) {
+      setValue('categoryId', '', { shouldDirty: false });
+      return;
+    }
+
+    setValue('categoryId', selectedCategoryId, { shouldDirty: false });
+  }, [categories, editingVisit, selectedCategoryId, setValue]);
+
   useEffect(() => {
     if (editingVisit) {
       setValue('start', editingVisit.date.start, { shouldDirty: false });
@@ -151,6 +189,7 @@ export function VisitForm({ editingVisit, onCompleted, onCancel, initialLocation
 
   async function onSubmit(values: VisitFormSchema) {
     const payload: VisitCreateInput = {
+      categoryId: values.categoryId ? values.categoryId : undefined,
       location: {
         country: values.country,
         city: values.city,
@@ -200,6 +239,23 @@ export function VisitForm({ editingVisit, onCompleted, onCancel, initialLocation
           fullWidth
         />
 
+        <TextField
+          select
+          label={t('form.category')}
+          {...register('categoryId')}
+          error={Boolean(errors.categoryId)}
+          helperText={errors.categoryId ? t(errors.categoryId.message ?? '') : ''}
+          fullWidth
+          SelectProps={{ displayEmpty: true }}
+        >
+          <MenuItem value="">{t('categories.uncategorized')}</MenuItem>
+          {categories.map((category) => (
+            <MenuItem key={category.id} value={category.id}>
+              {category.name}
+            </MenuItem>
+          ))}
+        </TextField>
+
         <Grid container spacing={2}>
           <Grid item xs={12} md={6}>
             <TextField

client/src/features/visits/components/VisitList.tsx

@@ -1,9 +1,11 @@
 import { useTranslation } from 'react-i18next';
+import { useMemo } from 'react';
 import { Button, Card, CardActions, CardContent, CircularProgress, Stack, Typography } from '@mui/material';
 import EditIcon from '@mui/icons-material/Edit';
 import DeleteIcon from '@mui/icons-material/Delete';
 import { useDeleteVisitMutation, useVisitsQuery } from '../hooks/useVisitQueries';
 import type { Visit } from '../types';
+import { useVisitCategorySelectionStore, UNCATEGORIZED_CATEGORY_ID } from '../../../state/useVisitCategorySelectionStore';
 
 interface VisitListProps {
   onEdit: (visit: Visit) => void;
@@ -13,6 +15,19 @@ export function VisitList({ onEdit }: VisitListProps) {
   const { data: visits = [], isLoading } = useVisitsQuery();
   const deleteMutation = useDeleteVisitMutation();
   const { t } = useTranslation();
+  const selectedCategoryId = useVisitCategorySelectionStore((state) => state.selectedCategoryId);
+
+  const filteredVisits = useMemo(() => {
+    if (!selectedCategoryId) {
+      return visits;
+    }
+
+    if (selectedCategoryId === UNCATEGORIZED_CATEGORY_ID) {
+      return visits.filter((visit) => !visit.categoryId);
+    }
+
+    return visits.filter((visit) => visit.categoryId === selectedCategoryId);
+  }, [visits, selectedCategoryId]);
 
   if (isLoading) {
     return (
@@ -25,17 +40,17 @@ export function VisitList({ onEdit }: VisitListProps) {
     );
   }
 
-  if (!visits.length) {
+  if (!filteredVisits.length) {
     return (
       <Typography variant="body2" color="text.secondary" sx={{ p: 3 }}>
-        {t('list.empty')}
+        {selectedCategoryId ? t('list.emptyForCategory') : t('list.empty')}
       </Typography>
     );
   }
 
   return (
     <Stack spacing={2} sx={{ p: 2 }}>
-      {visits.map((visit) => (
+      {filteredVisits.map((visit) => (
         <Card key={visit.id} variant="outlined">
           <CardContent>
             <Typography variant="h6" fontWeight={600} gutterBottom>

client/src/features/visits/components/VisitSummary.tsx

@@ -2,19 +2,33 @@ import { useMemo } from 'react';
 import { useTranslation } from 'react-i18next';
 import { Box, Card, CardContent, Typography } from '@mui/material';
 import { useVisitsQuery } from '../hooks/useVisitQueries';
+import { useVisitCategorySelectionStore, UNCATEGORIZED_CATEGORY_ID } from '../../../state/useVisitCategorySelectionStore';
 
 export function VisitSummary() {
   const { data: visits = [] } = useVisitsQuery();
   const { t } = useTranslation();
+  const selectedCategoryId = useVisitCategorySelectionStore((state) => state.selectedCategoryId);
+
+  const filteredVisits = useMemo(() => {
+    if (!selectedCategoryId) {
+      return visits;
+    }
+
+    if (selectedCategoryId === UNCATEGORIZED_CATEGORY_ID) {
+      return visits.filter((visit) => !visit.categoryId);
+    }
+
+    return visits.filter((visit) => visit.categoryId === selectedCategoryId);
+  }, [visits, selectedCategoryId]);
 
   const stats = useMemo(() => {
     const countries = new Set<string>();
-    visits.forEach((visit) => countries.add(visit.location.country));
+    filteredVisits.forEach((visit) => countries.add(visit.location.country));
     return {
-      totalVisits: visits.length,
+      totalVisits: filteredVisits.length,
       uniqueCountries: countries.size
     };
-  }, [visits]);
+  }, [filteredVisits]);
 
   const summaryItems = [
     { label: t('summary.totalVisits'), value: stats.totalVisits },

client/src/features/visits/context/VisitProvider.tsx

@@ -3,6 +3,8 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { localVisitRepository } from '../storage/localVisitRepository';
 import type { VisitRepository } from '../types';
 import { VisitApiClient } from '../api/visitApiClient';
+import type { VisitCategoryRepository } from '../../categories/types';
+import { localVisitCategoryRepository } from '../../categories/storage/localVisitCategoryRepository';
 
 export type VisitProviderMode = 'local' | 'api';
 
@@ -13,6 +15,7 @@ interface VisitProviderProps {
 }
 
 const VisitRepositoryContext = createContext<VisitRepository>(localVisitRepository);
+const VisitCategoryRepositoryContext = createContext<VisitCategoryRepository>(localVisitCategoryRepository);
 const queryClient = new QueryClient();
 
 export function VisitProvider({ children, mode = 'local', apiBaseUrl = '/api' }: VisitProviderProps) {
@@ -23,9 +26,15 @@ export function VisitProvider({ children, mode = 'local', apiBaseUrl = '/api' }:
     return localVisitRepository;
   }, [mode, apiBaseUrl]);
 
+  const categoryRepository = useMemo<VisitCategoryRepository>(() => {
+    return localVisitCategoryRepository;
+  }, []);
+
   return (
     <VisitRepositoryContext.Provider value={repository}>
-      <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+      <VisitCategoryRepositoryContext.Provider value={categoryRepository}>
+        <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+      </VisitCategoryRepositoryContext.Provider>
     </VisitRepositoryContext.Provider>
   );
 }
@@ -33,3 +42,7 @@ export function VisitProvider({ children, mode = 'local', apiBaseUrl = '/api' }:
 export function useVisitRepository(): VisitRepository {
   return useContext(VisitRepositoryContext);
 }
+
+export function useVisitCategoryRepository(): VisitCategoryRepository {
+  return useContext(VisitCategoryRepositoryContext);
+}

client/src/features/visits/storage/localVisitRepository.ts

@@ -1,6 +1,6 @@
 import { nanoid } from 'nanoid';
 import { loadFromStorage, saveToStorage } from '../../../lib/browserStorage';
-import type { Visit, VisitCreateInput, VisitId, VisitRepository, VisitUpdateInput } from '../types';
+import type { Visit, VisitRepository } from '../types';
 
 const STORAGE_KEY = 'traveling-around-the-world::visits';
 

client/src/locales/en/translation.json

@@ -5,7 +5,12 @@
   },
   "nav": {
     "openStreetMap": "OpenStreetMap",
-    "reactLeaflet": "React Leaflet"
+    "reactLeaflet": "React Leaflet",
+    "controls": "Quick Actions",
+    "controlsDescription": "Manage common settings and resources",
+    "links": "Resources",
+    "openControls": "More",
+    "close": "Close"
   },
   "language": {
     "label": "Language",
@@ -22,6 +27,23 @@
     "toggleOpen": "Show sidebar",
     "toggleClose": "Hide sidebar"
   },
+  "categories": {
+    "title": "Collections",
+    "addPlaceholder": "Name a new collection",
+    "addButton": "Add",
+    "all": "All",
+    "uncategorized": "Uncategorized",
+    "selectLabel": "Collection",
+    "manage": "Manage collections",
+    "edit": "Rename",
+    "delete": "Delete",
+    "renameTitle": "Rename collection",
+    "renamePlaceholder": "Enter a new name",
+    "renameSubmit": "Save",
+    "deleteTitle": "Delete collection",
+    "deleteMessage": "Delete \"{{name}}\"? Existing visits will move to Uncategorized.",
+    "deleteConfirm": "Delete"
+  },
   "summary": {
     "title": "Stats",
     "totalVisits": "Trips",
@@ -30,6 +52,7 @@
   "list": {
     "loading": "Loading...",
     "empty": "No trips recorded yet.",
+    "emptyForCategory": "No trips recorded in this collection yet.",
     "edit": "Edit",
     "delete": "Delete"
   },
@@ -44,6 +67,7 @@
     "notesPlaceholder": "Capture thoughts or reminders about the trip",
     "latitude": "Latitude",
     "longitude": "Longitude",
+    "category": "Collection",
     "cancel": "Cancel",
     "create": "Add Visit",
     "update": "Save Changes"

client/src/locales/zh-Hant/translation.json

@@ -5,7 +5,12 @@
   },
   "nav": {
     "openStreetMap": "OpenStreetMap",
-    "reactLeaflet": "React Leaflet"
+    "reactLeaflet": "React Leaflet",
+    "controls": "快速操作",
+    "controlsDescription": "管理常用設定與資源",
+    "links": "資源",
+    "openControls": "更多",
+    "close": "關閉"
   },
   "language": {
     "label": "語言",
@@ -22,6 +27,23 @@
     "toggleOpen": "展開側邊欄",
     "toggleClose": "收合側邊欄"
   },
+  "categories": {
+    "title": "旅程分類",
+    "addPlaceholder": "輸入新的分類名稱",
+    "addButton": "新增",
+    "all": "全部",
+    "uncategorized": "未分類",
+    "selectLabel": "分類",
+    "manage": "管理分類",
+    "edit": "重新命名",
+    "delete": "刪除",
+    "renameTitle": "重新命名分類",
+    "renamePlaceholder": "輸入新的名稱",
+    "renameSubmit": "儲存",
+    "deleteTitle": "刪除分類",
+    "deleteMessage": "確定要刪除「{{name}}」嗎？既有旅程會移至未分類。",
+    "deleteConfirm": "刪除"
+  },
   "summary": {
     "title": "統計",
     "totalVisits": "旅程數",
@@ -30,6 +52,7 @@
   "list": {
     "loading": "讀取中...",
     "empty": "目前尚未新增任何旅遊記錄。",
+    "emptyForCategory": "這個分類還沒有旅程。",
     "edit": "編輯",
     "delete": "刪除"
   },
@@ -44,6 +67,7 @@
     "notesPlaceholder": "留下旅程的感想或提醒",
     "latitude": "緯度",
     "longitude": "經度",
+    "category": "分類",
     "cancel": "取消",
     "create": "新增足跡",
     "update": "儲存變更"

client/src/state/useVisitCategorySelectionStore.ts

@@ -0,0 +1,21 @@
+import { create } from 'zustand';
+import { loadFromStorage, saveToStorage } from '../lib/browserStorage';
+
+export const UNCATEGORIZED_CATEGORY_ID = '__uncategorized__';
+const CATEGORY_SELECTION_STORAGE_KEY = 'traveling-around-the-world::selectedCategoryId';
+
+const initialSelectedCategoryId = loadFromStorage<string | null>(CATEGORY_SELECTION_STORAGE_KEY, null);
+
+interface VisitCategorySelectionState {
+  selectedCategoryId: string | null;
+  setSelectedCategoryId: (categoryId: string | null) => void;
+}
+
+export const useVisitCategorySelectionStore = create<VisitCategorySelectionState>((set) => ({
+  selectedCategoryId: initialSelectedCategoryId,
+  setSelectedCategoryId: (categoryId) =>
+    set(() => {
+      saveToStorage(CATEGORY_SELECTION_STORAGE_KEY, categoryId);
+      return { selectedCategoryId: categoryId };
+    })
+}));

shared/visit.ts

@@ -14,6 +14,7 @@ export interface VisitDateRange {
 
 export interface VisitDto {
   id: VisitId;
+  categoryId?: string;
   location: VisitLocation;
   date: VisitDateRange;
   notes?: string;