Complete LinkSyncServer and LinkSyncExtension implementation

LinkSyncServer:
- Fix app.py imports, add CORS middleware, lifespan events
- Create api/routes.py router aggregator
- Create config/settings.py for centralized configuration
- Rewrite models/base.py with proper relationships and serialization
- Rewrite all API endpoints with real DB integration (auth, links, collections, sync, queries, tags)
- Add admin endpoints (user management, stats, audit log)
- Complete query parser with recursive descent and proper precedence
- Complete query executor with set operations and field filters
- Set up Alembic migrations with initial schema
- Create web interface (templates, CSS, JS)
- Add 42 passing tests (auth, links, collections, queries)
- Add deploy.ps1 and deploy.sh scripts
- Update README with deployment workflow

LinkSyncExtension:
- Create utils/api.js (REST client with retries, auth, error handling)
- Create utils/sync.js (3 sync modes + conflict detection)
- Create utils/collection.js (collection management)
- Create utils/query-engine.js (client-side query parser)
- Rewrite background.js (sync loop, bookmark events, message routing)
- Rewrite popup.js (tabs, settings modal, notifications, CRUD)
- Update popup.html (tabbed interface, query builder, modal)
- Update popup.css (full redesign)
- Create content/content.js (page metadata extraction)
- Create options.html/js (dedicated settings page)
- Generate icons (48x48, 96x96)
- Update manifest.json (host permissions, content scripts, options)
- Create AGENTS.md

LinkSyncExtension/AGENTS.md

@@ -0,0 +1,106 @@
+# AGENTS.md - LinkSyncExtension
+
+## Project Overview
+
+LinkSyncExtension is a Firefox browser extension that synchronizes bookmarks with LinkSyncServer. It provides a popup UI for managing bookmarks, collections, and queries, with a background script handling automatic synchronization.
+
+## Architecture
+
+```
+LinkSyncExtension/
+├── manifest.json          # Firefox extension manifest v2
+├── popup.html/js/css      # Main popup UI (bookmarks, collections, queries)
+├── background.html/js     # Background page with sync engine
+├── options.html/js        # Dedicated settings page
+├── content/content.js     # Content script for page metadata extraction
+├── utils/
+│   ├── api.js             # REST API client with retries, auth, error handling
+│   ├── sync.js            # Sync engine (3 modes + conflict detection)
+│   ├── collection.js      # Collection management wrapper
+│   ├── query-engine.js    # Client-side query parser
+│   └── bookmark.js        # Bookmark parsing/merging utilities
+├── icons/
+│   ├── icon-48.png
+│   └── icon-96.png
+└── tests/
+    └── README.md          # Manual testing checklist
+```
+
+## Communication Pattern
+
+```
+popup.js/options.js ──browser.runtime.sendMessage──> background.js
+background.js ────────────────────────────────────> API (LinkSyncServer)
+background.js ──browser.bookmarks.*───────────────> Firefox bookmarks
+content.js ─────browser.runtime.onMessage─────────> popup.js
+```
+
+All API calls go through `utils/api.js`. The popup sends messages to the background script, which handles the actual API communication. This keeps the API token in the background context.
+
+## Key Modules
+
+### utils/api.js
+- `API.init()` - loads settings from storage
+- `API.request(method, path, body)` - core request with retries (3x), timeout (10s), rate limit handling
+- `API.login(username, password)` - authenticates and stores token
+- `API.testConnection()` - hits /health endpoint
+- CRUD methods for links, collections, queries, sync
+
+### utils/sync.js
+- `SyncEngine.runSync()` - main sync entry point
+- Three modes: bi-directional, browser-authoritative, server-authoritative
+- `SyncEngine.detectConflicts()` - finds title mismatches between browser and server
+- Uses `browser.bookmarks.getTree()` for local bookmarks
+
+### utils/query-engine.js
+- `QueryEngine.tokenize(expression)` - lexer
+- `QueryEngine.parse(expression)` - recursive descent parser
+- `QueryEngine.validate(expression)` - returns {valid, ast} or {valid, error}
+- Supports: TERM, TERM_SET, FIELD (url/tag/title/description/path/id), AND, OR, XOR, parentheses
+
+### background.js
+- Listens for `browser.runtime.onMessage` from popup/options
+- Handles bookmark change events (`onCreated`, `onChanged`, `onRemoved`)
+- Auto-sync timer (5 min interval when enabled)
+- Message types: SYNC_NOW, GET_SETTINGS, SAVE_SETTINGS, TEST_CONNECTION, LOGIN, GET_BOOKMARKS, CREATE_BOOKMARK, UPDATE_BOOKMARK, DELETE_BOOKMARK, GET_COLLECTIONS, EXECUTE_QUERY, PARSE_QUERY
+
+### popup.js
+- Tabbed interface: Bookmarks, Collections, Query
+- Settings modal (server URL, API key, sync mode, deletions, auto-sync)
+- Toast notifications (success/error/info, auto-dismiss after 3s)
+- Bookmark form with auto-fill from current tab
+- Search filter for bookmarks
+- Query builder with parse/execute buttons
+
+## Storage Keys
+
+| Key | Type | Description |
+|-----|------|-------------|
+| `linksync_server_url` | string | Server base URL |
+| `linksync_api_key` | string | JWT bearer token |
+| `linksync_sync_mode` | string | bi-directional / browser-authoritative / server-authoritative |
+| `linksync_deletions` | boolean | Enable deletions during sync |
+| `linksync_auto_sync` | boolean | Enable 5-minute auto-sync |
+| `linksync_last_sync` | string | ISO timestamp of last sync |
+| `linksync_syncing` | boolean | Currently syncing flag |
+| `linksync_pending` | boolean | Has pending local changes |
+
+## Testing
+
+Browser extensions require manual testing in Firefox:
+
+1. Open `about:debugging` in Firefox
+2. Click "This Firefox" → "Load Temporary Add-on"
+3. Select `manifest.json` from the project folder
+4. Click the extension icon to open the popup
+5. Right-click the icon → "Options" for settings page
+
+See `tests/README.md` for the full manual testing checklist.
+
+## Development Notes
+
+- Manifest v2 for Firefox compatibility
+- Background page (not service worker) for Firefox support
+- All API calls use Bearer token auth (matching server's JWT implementation)
+- Content script runs on all pages to extract metadata
+- No external dependencies - pure browser APIs