Use FastAPI BackgroundTasks and test sqlite-vector at startup

Co-authored-by: Mte90 <403283+Mte90@users.noreply.github.com>

Author: Copilot

ai/analyzer.py

@@ -422,19 +422,15 @@ def analyze_local_path_sync(
 
 def analyze_local_path_background(local_path: str, database_path: str, venv_path: Optional[str] = None, max_file_size: int = 200000, cfg: Optional[dict] = None):
     """
-    Non-blocking wrapper intended to be scheduled by FastAPI BackgroundTasks.
-    This function starts a daemon thread which runs the synchronous analyzer and returns immediately.
+    Wrapper intended to be scheduled by FastAPI BackgroundTasks.
+    This function runs the synchronous analyzer in the FastAPI background task.
     Usage from FastAPI endpoint:
         background_tasks.add_task(analyze_local_path_background, local_path, database_path, venv_path, max_file_size, cfg)
     """
-    def _worker():
-        try:
-            analyze_local_path_sync(local_path, database_path, venv_path=venv_path, max_file_size=max_file_size, cfg=cfg)
-        except Exception:
-            logger.exception("Background analysis worker failed for %s", local_path)
-
-    t = threading.Thread(target=_worker, name=f"analysis-worker-{os.path.basename(local_path)}", daemon=True)
-    t.start()
+    try:
+        analyze_local_path_sync(local_path, database_path, venv_path=venv_path, max_file_size=max_file_size, cfg=cfg)
+    except Exception:
+        logger.exception("Background analysis worker failed for %s", local_path)
 
 
 # Simple synchronous helpers preserved for compatibility --------------------------------

main.py

@@ -6,6 +6,7 @@
 from fastapi.staticfiles import StaticFiles
 from contextlib import asynccontextmanager
 import os
+import tempfile
 import uvicorn
 
 from db import operations as db_operations
@@ -28,6 +29,32 @@ async def lifespan(app: FastAPI):
     """Application lifespan handler."""
     global _file_watcher
 
+    # Test sqlite-vector extension loading at startup
+    logger.info("Testing sqlite-vector extension loading...")
+    try:
+        from db.vector_operations import connect_db, load_sqlite_vector_extension
+        
+        # Create a temporary database to test the extension
+        with tempfile.NamedTemporaryFile(suffix='.db', delete=False) as tmp:
+            tmp_db_path = tmp.name
+        
+        try:
+            conn = connect_db(tmp_db_path)
+            try:
+                load_sqlite_vector_extension(conn)
+                logger.info("✓ sqlite-vector extension loaded successfully")
+            finally:
+                conn.close()
+        finally:
+            # Clean up temporary database
+            try:
+                os.unlink(tmp_db_path)
+            except Exception:
+                pass
+    except Exception as e:
+        logger.error(f"FATAL: Failed to load sqlite-vector extension at startup: {e}")
+        raise RuntimeError(f"Cannot start application: sqlite-vector extension failed to load. {e}") from e
+    
     # Project registry is auto-initialized when needed via create_project
 
     # Auto-create default project from configured local_path if it exists