fix(confidence-engine): use configured model for chat detection

lib/llm/provider.js

@@ -60,7 +60,7 @@ function recoverJson(raw) {
 
 let _chatSupported = null;
 
-async function detectChatSupport(baseUrl) {
+async function detectChatSupport(baseUrl, modelName) {
   if (_chatSupported !== null) return _chatSupported;
   
   try {
@@ -68,7 +68,7 @@ async function detectChatSupport(baseUrl) {
       method: "POST",
       headers: { "Content-Type": "application/json" },
       body: JSON.stringify({
-        model: "dummy-check",
+        model: modelName,
         messages: [{ role: "user", content: "test" }],
         stream: false,
       }),
@@ -109,7 +109,7 @@ class OllamaLlmProvider {
     // Step 1: Detect whether /api/chat exists (cache result)
     // ================================================================
     try {
-      chatSupported = await detectChatSupport(baseUrl);
+      chatSupported = await detectChatSupport(baseUrl, modelName);
     } catch { /* failed silently — defaults to false */ }
 
     // ================================================================