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

entrypoint.sh

@@ -4,4 +4,5 @@
 envsubst < /app/templates/index.html.template > /app/templates/index.html
 
 # Start Gunicorn; using an environment variable for workers (default is 3)
+# TODO: Variable mismatch — example.env sets GUNICORN_WORKERS but this reads WORKERS. Change to ${GUNICORN_WORKERS:-3}.
 exec gunicorn --bind 0.0.0.0:8000 app:app --workers ${WORKERS:-3}