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

config/users.json

@@ -47,7 +47,7 @@
     "hashed_password": "$2b$12$IC9kz7kxf1mQPhsdveFnyOX3V5Q1.pB9/uqCKWI7nhn.SYamtvxCC",
     "is_active": true,
     "created_at": "2026-01-26T12:15:58.008205",
-    "last_login": "2026-02-27T09:06:22.312570"
+    "last_login": "2026-03-23T13:29:45.076454"
   },
   "testuser999": {
     "id": "f9abf4b8aa96d5116807ac1cf8540418",
@@ -78,5 +78,15 @@
     "is_active": true,
     "created_at": "2026-02-26T16:01:01.051127",
     "last_login": "2026-02-26T16:11:48.431566"
+  },
+  "fronttest": {
+    "id": "059c564b78528d334f5ac4ecce3ea894",
+    "username": "fronttest",
+    "email": "front@test.com",
+    "full_name": null,
+    "hashed_password": "$2b$12$qkZxcN9peGfWSj59ULm6S.5ROtFlF7fGXJpypD7cQ0N9TzDRl93z.",
+    "is_active": true,
+    "created_at": "2026-02-28T09:41:38.411958",
+    "last_login": "2026-03-01T16:24:30.918490"
   }
 }