Monorepo Integration: Unified Backend, Frontend & Documentation

- Reorganize project into monorepo structure
  - backend/app/ - New FastAPI backend (modular with src/)
  - backend/legacy/ - Legacy database modules (relational & vector)
  - frontend/ - React text editor application

- Add launcher.py for easy full-stack startup
- Complete documentation in README.md
  - Quick start guide
  - API endpoints reference
  - Development setup
  - Troubleshooting

- Refactor main.py to 35 lines (app configuration only)
- Update .gitignore for full-stack project
- Add CHANGELOG.md with version history (v0.1.0-v0.1.1)

Structure is now clean and ready for team collaboration.

frontend/public/manifest.json

@@ -0,0 +1,25 @@
+{
+  "short_name": "React App",
+  "name": "Create React App Sample",
+  "icons": [
+    {
+      "src": "favicon.ico",
+      "sizes": "64x64 32x32 24x24 16x16",
+      "type": "image/x-icon"
+    },
+    {
+      "src": "logo192.png",
+      "type": "image/png",
+      "sizes": "192x192"
+    },
+    {
+      "src": "logo512.png",
+      "type": "image/png",
+      "sizes": "512x512"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#000000",
+  "background_color": "#ffffff"
+}