fix: increase timeout for Ollama and local LLM operations

Users with Ollama reported timeout errors on notebook chat while the
backend was still processing. The answer would appear after refresh.

- Frontend axios timeout: 5 min → 10 min
- Backend chat service timeout: 2 min → 10 min

Local LLMs can take several minutes for complex questions with large
contexts, especially on slower hardware.

api/chat_service.py

@@ -135,7 +135,7 @@ class ChatService:
             if model_override is not None:
                 data["model_override"] = model_override
             
-            async with httpx.AsyncClient(timeout=120.0) as client:  # Longer timeout for chat
+            async with httpx.AsyncClient(timeout=600.0) as client:  # 10 min timeout for Ollama/local LLMs
                 response = await client.post(
                     f"{self.base_url}/api/chat/execute",
                     json=data,

frontend/src/lib/api/client.ts

@@ -3,12 +3,12 @@ import { getApiUrl } from '@/lib/config'
 
 // API client with runtime-configurable base URL
 // The base URL is fetched from the API config endpoint on first request
-// Timeout increased to 5 minutes (300000ms = 300s) to accommodate slow LLM operations
-// (transformations, insights generation) especially on slower hardware (Ollama, LM Studio)
-// Note: Frontend uses milliseconds (300000ms), backend uses seconds (300s) - both equal 5 minutes
-// To configure: Set API_CLIENT_TIMEOUT=600 in .env for 10 minutes (600s = 600000ms)
+// Timeout increased to 10 minutes (600000ms = 600s) to accommodate slow LLM operations
+// (transformations, insights generation, chat) especially on slower hardware (Ollama, LM Studio)
+// Note: Frontend uses milliseconds, backend uses seconds
+// Local LLMs can take several minutes for complex questions with large contexts
 export const apiClient = axios.create({
-  timeout: 300000, // 300 seconds = 5 minutes
+  timeout: 600000, // 600 seconds = 10 minutes
   headers: {
     'Content-Type': 'application/json',
   },