Fix Docker deployment and add Tailscale Funnel support

- Fix argon2 native module build in Docker (add build-essential, python3)
- Switch Docker base image from Alpine to Debian-slim for OpenSSL compatibility
- Fix session cookies for HTTP access (COOKIE_SECURE env var)
- Fix TypeScript type errors in sync routes and middleware
- Fix CSS circular dependency in globals.css
- Fix Map iteration in rate-limit cleanup
- Add createdAt field to LocalNote interface
- Configure Tailscale Funnel on port 10000
- Update NEXT_PUBLIC_APP_URL for public funnel access
- Add initial Prisma migration

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.eslintrc.json

@@ -1,7 +1,6 @@
 {
   "extends": ["next/core-web-vitals"],
   "rules": {
-    "@typescript-eslint/no-unused-vars": ["warn", { "argsIgnorePattern": "^_" }],
     "react/no-unescaped-entities": "off"
   }
 }