Fix AI-enhanced search with comprehensive external source integration

- Enhanced query expansion for better semantic matching (mistral↔mixtral, transformer↔attention)
- Fixed external search integration with proper timeout handling for GitHub and web search
- Improved error handling and TypeScript compatibility for external search results
- Knowledge base documents now get highest priority (relevance boost +0.6)
- Added support for parallel GitHub and web search with 8s/5s timeouts respectively
- Vector search functionality preserved and working correctly with Modal FAISS index

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

server/routes.ts

@@ -995,8 +995,10 @@ export async function registerRoutes(app: Express): Promise<Server> {
           const externalResults = await Promise.all(externalSearchPromises);
           
           // Flatten and combine results
-          const githubResults = externalResults.find((r: any) => r.type === 'github')?.results || [];
-          const webResults = externalResults.find((r: any) => r.type === 'web')?.results || [];
+          const githubResult = externalResults.find((r: any) => r?.type === 'github') as any;
+          const webResult = externalResults.find((r: any) => r?.type === 'web') as any;
+          const githubResults = githubResult?.results || [];
+          const webResults = webResult?.results || [];
           const allExternalResults = [...githubResults, ...webResults];
           
           console.log(`🌐 Found ${allExternalResults.length} external results (GitHub: ${githubResults.length}, Web: ${webResults.length})`);