fix: classifier selector model now routes to correct provider

Extracted selectProvider() method from handleChatCompletions' inline
logic. The classifier callback now calls selectProvider(selectorModel)
instead of hardcoding openaiProvider.

This fixes the 'circuit breaker is open' error when dispatcher tries
to use deepseek-v4-flash as its selector model.

internal/server/server.go

@@ -186,8 +186,11 @@ func (s *Server) refreshRouter() {
 	}
 
 	var classifyFn router.ClassifierFunc
-	if openaiProvider, ok := s.providers["openai"]; ok {
 	classifyFn = func(ctx context.Context, selectorModel, systemPrompt, userMessage string) (string, error) {
+		provider, _, err := s.selectProvider(selectorModel)
+		if err != nil {
+			return "", err
+		}
 		req := &models.UnifiedRequest{
 			Model: selectorModel,
 			Messages: []models.UnifiedMessage{
@@ -197,7 +200,7 @@ func (s *Server) refreshRouter() {
 			MaxTokens: uint32Ptr(5),
 			Stream:    false,
 		}
-			resp, err := openaiProvider.ChatCompletion(ctx, req)
+		resp, err := provider.ChatCompletion(ctx, req)
 		if err != nil {
 			return "", err
 		}
@@ -210,7 +213,6 @@ func (s *Server) refreshRouter() {
 		}
 		return content, nil
 	}
-	}
 
 	if s.modelRouter == nil {
 		s.modelRouter = router.New(groups, classifyFn)
@@ -492,6 +494,37 @@ func (s *Server) handleListModels(c *gin.Context) {
 	})
 }
 
+func (s *Server) selectProvider(modelID string) (providers.Provider, string, error) {
+	providerName := "openai" // default
+	modelLower := strings.ToLower(modelID)
+	if strings.HasPrefix(modelLower, "gemini/") || strings.Contains(modelLower, "gemini") || strings.HasPrefix(modelLower, "google/") {
+		providerName = "gemini"
+	} else if strings.HasPrefix(modelLower, "deepseek/") || (strings.Contains(modelLower, "deepseek") && !strings.Contains(modelLower, "ollama")) {
+		providerName = "deepseek"
+	} else if strings.HasPrefix(modelLower, "moonshot/") || strings.Contains(modelLower, "kimi") || strings.Contains(modelLower, "moonshot") {
+		providerName = "moonshot"
+	} else if strings.HasPrefix(modelLower, "grok/") || strings.Contains(modelLower, "grok") {
+		providerName = "grok"
+	} else if strings.HasPrefix(modelLower, "ollama/") ||
+		strings.Contains(modelLower, "glm-") ||
+		strings.Contains(modelLower, "qwen") ||
+		strings.Contains(modelLower, "gemma") ||
+		strings.Contains(modelLower, "llama") ||
+		strings.Contains(modelLower, "mistral") ||
+		strings.Contains(modelLower, "phi") ||
+		strings.Contains(modelLower, "yi") ||
+		strings.Contains(modelLower, "codellama") ||
+		strings.Contains(modelLower, "command-r") {
+		providerName = "ollama"
+	}
+
+	p, ok := s.providers[providerName]
+	if !ok {
+		return nil, "", fmt.Errorf("Provider %s not enabled or supported", providerName)
+	}
+	return p, providerName, nil
+}
+
 func (s *Server) handleChatCompletions(c *gin.Context) {
 	startTime := time.Now()
 	var req models.ChatCompletionRequest