refactor: convert frontend from submodule to true monorepo

Convert frontend from Git submodule to a regular monorepo directory for simplified development workflow.

Changes:
- Remove frontend submodule tracking (mode 160000 gitlink)
- Add all frontend source files directly to main repository
- Remove frontend/.git directory
- Update CLAUDE.md to clarify true monorepo structure
- Update Frontend Architecture documentation (React Router v6, Socket.IO, Leaflet, ErrorBoundary)

Benefits of Monorepo:
- Single git clone for entire project
- Unified commit history
- Simpler CI/CD pipeline
- Easier for new developers
- No submodule sync issues
- Atomic commits across frontend and backend

Frontend Files Added:
- All React components (MapView, ErrorBoundary, TaskList, SocialFeed, etc.)
- Context providers (AuthContext, SocketContext)
- Complete test suite with MSW
- Dependencies and configuration files

Branch Cleanup:
- Using 'main' as default branch (develop deleted)
- Frontend no longer has separate Git history

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/package.json

@@ -0,0 +1,70 @@
+{
+  "name": "frontend",
+  "version": "0.1.0",
+  "private": true,
+  "dependencies": {
+    "@stripe/stripe-js": "^6.0.0",
+    "@testing-library/dom": "^10.4.0",
+    "@testing-library/jest-dom": "^6.6.3",
+    "@testing-library/react": "^16.2.0",
+    "@testing-library/user-event": "^13.5.0",
+    "axios": "^1.8.3",
+    "leaflet": "^1.9.4",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
+    "react-leaflet": "^5.0.0",
+    "react-leaflet-cluster": "^1.0.3",
+    "react-router-dom": "^6.28.0",
+    "react-scripts": "5.0.1",
+    "react-toastify": "^11.0.5",
+    "socket.io-client": "^4.8.1",
+    "web-vitals": "^2.1.4"
+  },
+  "proxy": "http://localhost:5000",
+  "scripts": {
+    "start": "react-scripts start",
+    "build": "react-scripts build",
+    "test": "react-scripts test",
+    "test:coverage": "react-scripts test --coverage --watchAll=false",
+    "test:watch": "react-scripts test",
+    "eject": "react-scripts eject"
+  },
+  "jest": {
+    "collectCoverageFrom": [
+      "src/**/*.{js,jsx}",
+      "!src/index.js",
+      "!src/reportWebVitals.js",
+      "!src/setupTests.js",
+      "!src/mocks/**"
+    ],
+    "coverageThreshold": {
+      "global": {
+        "branches": 50,
+        "functions": 60,
+        "lines": 60,
+        "statements": 60
+      }
+    }
+  },
+  "eslintConfig": {
+    "extends": [
+      "react-app",
+      "react-app/jest"
+    ]
+  },
+  "browserslist": {
+    "production": [
+      ">0.2%",
+      "not dead",
+      "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
+    ]
+  },
+  "devDependencies": {
+    "msw": "^2.11.6"
+  }
+}