feat: add model picker on non-ollama llm

backend/internal/ai/pipeline.go

@@ -39,15 +39,7 @@ func (p *Pipeline) IsGenerating() bool {
 }
 
 func (p *Pipeline) BuildProvider(name, apiKey, endpoint string) (Provider, error) {
-	provider, err := p.repo.GetActiveAIProvider()
-	if err != nil {
-		return nil, err
-	}
-	model := ""
-	if provider != nil {
-		model = provider.Model
-	}
-	return NewProvider(name, apiKey, model, endpoint)
+	return NewProvider(name, apiKey, "", endpoint)
 }
 
 // buildProviderForRole resolves and builds the AI provider for a given task role.