#202 Apps: Implement API endpoints for app registry

## Parent Epic: #195 ## Description Create API endpoints for app registry CRUD operations. ## Location api/blueprints/v1/apps.py ## Endpoints ### App Registry (requires register_apps/update_apps/delete_apps) POST /api/v1/apps - Register new app - Body: {app_name, display_name, description, category, tags, visibility} - Permission: register_apps GET /api/v1/apps - List apps with pagination/filters - Query: page, page_size, category, status, visibility - Permission: view_apps GET /api/v1/apps/{app_id} - Get app details with versions - Permission: view_apps PATCH /api/v1/apps/{app_id} - Update app metadata - Permission: update_apps DELETE /api/v1/apps/{app_id} - Soft delete app - Permission: delete_apps ### Version Management POST /api/v1/apps/{app_id}/versions - Create new version (draft) - Body: {version, entrypoint_type, entrypoint_config, actions, configuration_schema, required_secrets} - Permission: update_apps GET /api/v1/apps/{app_id}/versions - List all versions - Permission: view_apps GET /api/v1/apps/{app_id}/versions/{version_id} - Get version details - Permission: view_apps POST /api/v1/apps/{app_id}/versions/{version_id}/publish - Publish draft version - Permission: publish_apps POST /api/v1/apps/{app_id}/versions/{version_id}/deprecate - Deprecate version - Permission: update_apps ### Discovery GET /api/v1/apps/marketplace - Browse public/tenant apps - Permission: view_apps GET /api/v1/apps/categories - List categories - Permission: view_apps GET /api/v1/apps/search - Search apps - Query: q, category, tags - Permission: view_apps ## Response Format Standard response.py patterns with pagination ## Error Handling - 400: Invalid input - 403: Permission denied - 404: App/version not found - 409: Conflict (duplicate name) ## Testing - API integration tests - Permission tests - Pagination tests - Error handling tests