Add Supabase key validation and simplify frontend state management

- Add backend validation to detect and warn about anon vs service keys
- Prevent startup with incorrect Supabase key configuration
- Consolidate frontend state management following KISS principles
- Remove duplicate state tracking and sessionStorage polling
- Add clear error display when backend fails to start
- Improve .env.example documentation with detailed key selection guide
- Add comprehensive test coverage for validation logic
- Remove unused test results checking to eliminate 404 errors

The implementation now warns users about key misconfiguration while
maintaining backward compatibility. Frontend state is simplified with
MainLayout as the single source of truth for backend status.

archon-ui-main/Dockerfile

@@ -21,5 +21,9 @@ COPY . .
 # Expose Vite's default port
 EXPOSE 5173
 
+# Add a small startup script to wait a moment before starting Vite
+# This helps ensure the backend is fully ready even after healthcheck passes
+RUN echo '#!/bin/sh\nsleep 3\nexec npm run dev -- --host 0.0.0.0' > /app/start.sh && chmod +x /app/start.sh
+
 # Start Vite dev server with host binding for Docker
-CMD ["npm", "run", "dev", "--", "--host", "0.0.0.0"] 
+CMD ["/app/start.sh"]