fix: correct marquee scroll speed and add code TODOs

- Fixed scrolling marquee to use a fixed px/s speed via JS instead of
  a fixed duration, preventing it from speeding up as entries are added
- Added inline TODO comments throughout codebase to track known issues
  (rate limiting, CSRF, unbounded queries, deprecated Flask decorator,
  PII logging, schema versioning, Docker non-root user, etc.)
- Added todo-to-issue GitHub Action to auto-create Issues from TODOs on push to main
- Added .claude/ to .gitignore

.gitignore

@@ -184,5 +184,8 @@ cython_debug/
 # VS Code
 .vscode/
 
+# Claude Code
+.claude/
+
 .env
 docker-compose.yml