feat(linter): implement Phase 1 linter automation and docs

- Add .clang-tidy (analyzer + selected bugprone) and .clang-format (LLVM, 4-space, 100 cols)
- Enhance scripts/run-linter.sh to use compile_commands.json when available
- Add scripts/setup-hooks.sh pre-commit (format enforcement; advisory tidy)
- Update azure-pipelines.yml to export compile_commands and run clang-tidy -p build
- Fill docs/linter-setup.md and docs/coding-standards.md for Phase 1
- Add minimal tests in tests/test_main.cpp to ensure CI executes
- Rewrite README with Phase 1 workflow

.clang-tidy

@@ -0,0 +1,31 @@
+Checks: >
+  -*,
+  clang-analyzer-*,
+  bugprone-argument-comment,
+  bugprone-assert-side-effect,
+  bugprone-bad-signal-to-kill-thread,
+  bugprone-branch-clone,
+  bugprone-copy-constructor-init,
+  bugprone-dangling-handle,
+  bugprone-exception-escape,
+  bugprone-integer-division,
+  bugprone-macro-parentheses,
+  bugprone-misplaced-operator-in-strlen-in-alloc,
+  bugprone-multiple-new-delete-leaks,
+  bugprone-sizeof-expression,
+  bugprone-suspicious-missing-comma,
+  bugprone-throw-keyword-missing,
+  bugprone-unhandled-self-assignment,
+  bugprone-unused-return-value,
+  clang-analyzer-security.*,
+  clang-analyzer-cplusplus.*,
+  clang-analyzer-core.*
+HeaderFilterRegex: '(src|tests)/'
+AnalyzeTemporaryDtors: false
+FormatStyle: none
+WarningsAsErrors: ''
+
+# Phase 1: advisory only (warnings do not fail CI)
+CheckOptions:
+  - key:             bugprone-assert-side-effect.AssertMacros
+    value:           'assert'