feat(email): add SMTP security modes (starttls/ssl/none) with sensible default ports; add /notify_test endpoint; support ALWAYS_NOTIFY_ON_STARTUP to force first-run notification

chore(docker): run enhanced_crawler.py as entrypoint

ops(compose): load env via env_file and remove hardcoded secrets

docs: update README and .env.template for SMTP and startup notification

.env.template

@@ -1,10 +1,13 @@
 # 基本設定
 CHECK_INTERVAL=300
 LOG_LEVEL=INFO
+ALWAYS_NOTIFY_ON_STARTUP=false
 
 # 電子郵件通知設定（Gmail 範例）
 EMAIL_SMTP_SERVER=smtp.gmail.com
 EMAIL_SMTP_PORT=587
+# 可選: starttls | ssl | none
+EMAIL_SMTP_SECURITY=starttls
 EMAIL_FROM=your_email@gmail.com
 EMAIL_TO=notification@gmail.com
 EMAIL_USERNAME=your_email@gmail.com
@@ -14,4 +17,4 @@ EMAIL_PASSWORD=your_app_specific_password
 WEBHOOK_URL=https://hooks.slack.com/services/YOUR/SLACK/WEBHOOK
 
 # Discord Webhook（可選）
-DISCORD_WEBHOOK=https://discord.com/api/webhooks/YOUR/DISCORD/WEBHOOK
+DISCORD_WEBHOOK=https://discord.com/api/webhooks/YOUR/DISCORD/WEBHOOK