fix: improve CodexLens env defaults, self-exclusion, and route handling

- Adjust env defaults (embed batch 64, workers 2) and add HNSW/chunking params
- Exclude .codexlens directory from indexing and file watching
- Expand codexlens-routes with improved validation and error handling
- Enhance integration tests for broader route coverage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ccw/frontend/src/lib/api.ts

@@ -237,7 +237,7 @@ export async function initializeCsrfToken(): Promise<void> {
 /**
  * Base fetch wrapper with CSRF token and error handling
  */
-async function fetchApi<T>(
+export async function fetchApi<T>(
   url: string,
   options: RequestInit = {}
 ): Promise<T> {