refactor: migrate main.py to modular routers and add project roadmap

- Migrated monolithic main.py to feature-scoped routers in app/routers/
- Added GEMINI.md for project context and AI instructional guidelines
- Updated README.md with a comprehensive modernization plan (SQL migration, robust scraping DSL, frontend modernization)
- Improved authentication with cookie support and modular JS
- Updated test suite and documentation

static/js/__tests__/smoke.test.js

@@ -0,0 +1,8 @@
+// Smoke test to verify Vitest setup
+import { describe, it, expect } from 'vitest';
+
+describe('smoke', () => {
+  it('works', () => {
+    expect(true).toBe(true);
+  });
+});