fix: safe services initialization and robust health check

main.py

@@ -282,6 +282,9 @@ async def root():
 )
 async def list_models():
     """List all available AI models across all providers."""
+    if not engine:
+        return ModelsResponse(models=[], total=0)
+        
     models = engine.get_all_models()
     return ModelsResponse(
         models=models,
@@ -297,9 +300,17 @@ async def list_models():
 async def health_check():
     """
     Run health checks on all providers.
-
-    Returns the status of each provider and overall system health.
     """
+    if not engine:
+        return HealthResponse(
+            status="unhealthy",
+            version="2.0.0",
+            uptime=0, # TODO: Track uptime
+            providers={},
+            error="AI Engine failed to initialize (check logs)"
+        )
+        
+    # Get provider health
     logger.info("Running health checks...")
     results = await engine.health_check_all()
 

services.py

@@ -1,6 +1,23 @@
 from engine import AIEngine
 from search_engine import SearchEngine
 
-# Singleton instances to be shared across modules
-engine = AIEngine()
-search_engine = SearchEngine()
+import logging
+import traceback
+
+logger = logging.getLogger("kai_api.services")
+
+# Singleton instances placeholder
+engine = None
+search_engine = None
+
+try:
+    engine = AIEngine()
+    search_engine = SearchEngine()
+    logger.info("✅ Services initialized successfully")
+except Exception as e:
+    logger.error(f"❌ Failed to initialize services: {e}")
+    logger.error(traceback.format_exc())
+    # We don't raise here to allow the app to start (and report error via /health)
+    # But wait, if engine is None, v1_router will crash when accessed.
+    # We should define a dummy engine? Or handle None in routers.
+

v1_router.py

@@ -184,6 +184,9 @@ async def chat_completions(
     provider = request.provider or "auto"
     
     try:
+        if not engine:
+            raise HTTPException(status_code=503, detail="AI Engine is not initialized (Startup Error)")
+            
         result = await engine.chat(
             prompt=user_prompt,
             model=request.model,