Improve model status indicators and tune timeouts

Green/red emoji circles replace Unicode symbols for at-a-glance model
readiness. Increase connect timeouts (10→30s) for cold model loading,
warm timeout (120→300s) for large models, and pull timeout (600→1800s)
to match route-level limit. Show error toast on SSE reconnection failure
instead of silently recovering.

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

src/fabledassistant/routes/chat.py

@@ -269,7 +269,7 @@ async def warm_model_route():
 
     async def _warm():
         try:
-            async with httpx.AsyncClient(timeout=120.0) as client:
+            async with httpx.AsyncClient(timeout=300.0) as client:
                 await client.post(
                     f"{Config.OLLAMA_URL}/api/generate",
                     json={"model": model, "prompt": "", "keep_alive": "30m"},