fix: resolve CI test failures and code review issues

- Add missing response for 'clear' command in worker message handler
- Remove duplicate response with hardcoded ID in clearIndex method
- Make CodeIndexManager.disposeAll() async and await it in extension deactivation
- Update unit tests to reflect new worker-based architecture
- Add indexing-worker.ts to knip ignore list to fix unused file warning

src/workers/indexing-worker.ts

@@ -52,6 +52,7 @@ class IndexingWorker {
 
 				case "clear":
 					await this.clearIndex()
+					this.sendResponse(id, { type: "cleared", success: true })
 					break
 
 				case "search": {
@@ -197,7 +198,6 @@ class IndexingWorker {
 		}
 		await this.orchestrator.clearIndexData()
 		await this.cacheManager.clearCacheFile()
-		this.sendResponse("clear", { type: "cleared", success: true })
 	}
 
 	private async search(query: string, directoryPrefix?: string): Promise<VectorStoreSearchResult[]> {