feat: add standalone web UI — tickets page with same style as homelab-dashboard

- corvid/templates/base.html: simplified nav (Corvid logo, Tickets link only),
  no user footer, no SSO — identical dark theme and component styles
- corvid/templates/tickets.html: copied verbatim from homelab-dashboard
  (all API paths are relative, no user-specific references)
- corvid/main.py: /tickets HTML route + / redirect; templates loaded from
  package dir so they work whether installed or run from source
- corvid/router.py: allow open access when TICKETS_API_KEY is not set
  (local/dev mode) — set the key to require auth for external access
- pyproject.toml: add jinja2>=3.1 dependency

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile

@@ -8,6 +8,7 @@ COPY alembic.ini .
 COPY alembic/ alembic/
 COPY corvid/ corvid/
 COPY entrypoint.sh .
+# templates are bundled inside corvid/ package dir — no extra COPY needed
 RUN chmod +x entrypoint.sh
 
 EXPOSE 8080