Switch from voice_ask to ask_wellnuo_ai API function

As requested - same parameters, same response format.
Changed in both:
- chat.tsx (text chat)
- agent.py (voice agent)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/(tabs)/chat.tsx

@@ -248,11 +248,12 @@ export default function ChatScreen() {
       const normalizedQuestion = normalizeQuestion(trimmedInput);
 
       // Call API with EXACT same params as voice agent
+      // Using ask_wellnuo_ai instead of voice_ask (same params, same response format)
       const response = await fetch(API_URL, {
         method: 'POST',
         headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
         body: new URLSearchParams({
-          function: 'voice_ask',
+          function: 'ask_wellnuo_ai',
           clientId: 'MA_001',
           user_name: WELLNUO_USER,
           token: token,

julia-agent/julia-ai/src/agent.py

@@ -191,8 +191,9 @@ class WellNuoLLM(llm.LLM):
             token = await self._ensure_token()
 
             async with aiohttp.ClientSession() as session:
+                # Using ask_wellnuo_ai instead of voice_ask (same params, same response)
                 data = {
-                    "function": "voice_ask",
+                    "function": "ask_wellnuo_ai",
                     "clientId": "MA_001",
                     "user_name": WELLNUO_USER,
                     "token": token,