fix(deploy): resolve Docker startup and CSRF issues

- Rename TASKPLANER_DATA_DIR to DATA_DIR (avoid adapter-node envPrefix conflict)
- Add TASKPLANER_ORIGIN for CSRF protection in docker-compose.yml
- Add automatic database schema initialization on startup
- Add Playwright E2E tests for Docker deployment verification
- Update .env.example with correct variable names

Fixes container restart loop and 403 errors on form submission.

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

Dockerfile

@@ -40,7 +40,7 @@ USER nodejs
 
 # Set environment variables
 ENV NODE_ENV=production
-ENV TASKPLANER_DATA_DIR=/app/data
+ENV DATA_DIR=/app/data
 ENV PORT=3000
 
 # Expose port