fix(ai): primary -> mlx-proxy 8801 + align model to gemma

- endpoint: 100.76.254.116:8800 -> :8801 (route through mlx-proxy for
  /status observability - active_jobs / total_requests)
- model: Qwen3.5-35B-A3B-4bit -> gemma-4-26b-a4b-it-8bit (match the
  model actually loaded on mlx-proxy)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

config.yaml

@@ -6,8 +6,8 @@ ai:
 
   models:
     primary:
-      endpoint: "http://100.76.254.116:8800/v1/chat/completions"
-      model: "mlx-community/Qwen3.5-35B-A3B-4bit"
+      endpoint: "http://100.76.254.116:8801/v1/chat/completions"
+      model: "mlx-community/gemma-4-26b-a4b-it-8bit"
       max_tokens: 4096
       timeout: 60