feat: implement parallel document indexing in IndexingPipelineService

- Added `index_batch_parallel` method to enable concurrent indexing of documents with bounded concurrency, improving performance and efficiency.
- Refactored existing indexing logic to utilize `asyncio.to_thread` for non-blocking execution of embedding and chunking functions.
- Introduced unit tests to validate the functionality of the new parallel indexing method, ensuring robustness and error handling during document processing.

surfsense_web/contracts/enums/toolIcons.tsx

@@ -5,10 +5,10 @@ import {
 	FileText,
 	Film,
 	Globe,
+	ImageIcon,
 	type LucideIcon,
 	Podcast,
 	ScanLine,
-	Sparkles,
 	Wrench,
 } from "lucide-react";
 
@@ -17,7 +17,7 @@ const TOOL_ICONS: Record<string, LucideIcon> = {
 	generate_podcast: Podcast,
 	generate_video_presentation: Film,
 	generate_report: FileText,
-	generate_image: Sparkles,
+	generate_image: ImageIcon,
 	scrape_webpage: ScanLine,
 	web_search: Globe,
 	search_surfsense_docs: BookOpen,