feat: implement collection library filter with WebSocket improvements and test coverage

This commit adds comprehensive functionality for filtering collections by library,
improves WebSocket real-time updates with user activity detection, and adds
extensive test coverage.

## Core Features

### Collection Library Filter
- Added library_id parameter to media-items search API
- Collections can now be filtered by specific library
- Toggle UI component for enabling/disabling library filter
- Default state is "checked" when library_id is present
- Consistent behavior across partial and fuzzy search modes

### WebSocket Auto-Reload Mitigation
- Added user activity detection to prevent disruptive page reloads
- Checks if user is actively typing in INPUT/TEXTAREA/SELECT elements
- Skips auto-reload when user is interacting with form elements
- Toast notifications still show for awareness
- Prevents data loss during editing operations

## Implementation Changes

### Backend
- internal/database/queries.sql.go: Added library filter support to search queries
- internal/handlers/media.go: Enhanced search with library_id parameter validation
- internal/handlers/collections.go: Updated collection handlers with library filtering
- internal/sync/websocket.go: Improved broadcast mechanism with user-scoped updates
- internal/router/frontend.go: Pass libraryID to collection templates

### Frontend
- templates/collections.templ: Added library filter toggle UI component
- web/src/collections.ts: TypeScript implementation with WebSocket integration
- templates/collections_templ.go: Generated template code

### Testing
- cmd/server/tests/search_test.go: Added TestCollectionSearchLibraryFilter
- cmd/server/tests/websocket_test.go: Added TestWebSocketUserScopedBroadcast
- New helper functions for creating libraries and media items via API
- Comprehensive test coverage for library filtering and user-scoped broadcasts

## API Documentation Updates

### Bruno Tests (Comprehensive Documentation)
- bruno/collections/*: Added detailed API documentation for all collection endpoints
- bruno/devices/*: Added device management and sync API documentation
- bruno/devices/kobo/api.yml: Kobo-specific sync protocol docs
- bruno/devices/koreader/api.yml: KOReader-specific sync protocol docs
- bruno/opds/*: Added OPDS feed and download endpoint documentation
- bruno/library/browse-folders.yml: Library folder browsing API docs

### New Bruno Tests
- bruno/media-items/Search All Libraries.yml: Test search without library filter
- bruno/media-items/Search Specific Library.yml: Test search with library filter
- bruno/media-items/Search Invalid Library ID.yml: Test error handling

## Documentation

- docs/developer/api/media-items/search_media_items.md: Updated with library_id parameter
- IMPLEMENTATION_COLLECTION_FIX.md: Comprehensive implementation guide with test scenarios

## Testing

### Integration Tests
- Library filter tests verify correct filtering across multiple libraries
- Invalid library_id tests ensure proper error handling
- WebSocket tests verify user-scoped broadcast behavior
- User A no longer receives User B's collection updates

### Manual Testing Scenarios
- Open collection in multiple tabs - updates propagate correctly
- Type in search box while another tab adds books - no disruptive reload
- Add/remove books from collection - toast notifications appear
- Toggle library filter - results update dynamically

## Technical Details

- WebSocket broadcasts are now user-scoped for privacy
- Active element detection uses tagName and contenteditable attributes
- Library ID validation uses UUID format checking
- Progressive enhancement maintained - page works without JavaScript
- All changes follow PROJECT_GUIDELINES.md conventions
- TypeScript only for frontend logic
- TailwindCSS only for styling
- Procedural programming style throughout

## Breaking Changes

None - all changes are additive and backward compatible.

bruno/collections/Update Collection.yml

@@ -13,3 +13,34 @@ http:
       auto_assign_rules\": [\n      {\n        \"id\": \"rule-2\",\n        \"field\"\
       : \"series\",\n        \"operator\": \"equals\",\n        \"value\": \"Foundation\"\
       ,\n        \"priority\": 9"
+
+docs: |-
+  ## Update Collection
+  
+    Updates an existing collection's properties.
+    
+    **Method:** PUT
+    
+    **Endpoint:** /api/collections/{collection_id}
+    
+    **Authentication:** Required (Bearer token)
+    
+    **Path Parameters:**
+    - `collection_id` (string): Collection ID
+    
+    **Request Body:**
+    - `name` (string, optional): New collection name
+    - `description` (string, optional): New description
+    - `color` (string, optional): New hex color code
+    - `icon` (string, optional): New emoji icon
+    - `auto_assign_rules` (array, optional): Updated auto-assignment rules
+    
+    **Response:**
+    - Updated collection object
+    
+    **Status Codes:**
+    - 200: Success
+    - 400: Invalid request
+    - 401: Unauthorized
+    - 404: Collection not found
+    - 409: Collection name already exists