Add Stealth model to AstraChat provider using big-pickle on opencode zen

app/lib/modules/llm/providers/astrachat.ts

@@ -15,6 +15,7 @@ export default class AstraChatProvider extends BaseProvider {
   staticModels: ModelInfo[] = [
     { name: 'Kimi K2 0905', label: 'Kimi K2 0905', provider: 'AstraChat', maxTokenAllowed: 4096 },
     { name: 'Grok Code Fast 1', label: 'Grok Code Fast 1', provider: 'AstraChat', maxTokenAllowed: 4096 },
+    { name: 'Stealth', label: 'Stealth', provider: 'AstraChat', maxTokenAllowed: 4096 },
   ];
 
   async getDynamicModels(
@@ -41,6 +42,13 @@ export default class AstraChatProvider extends BaseProvider {
       })('grok-code');
     }
 
+    if (options.model === 'Stealth') {
+      return createOpenAI({
+        baseURL: 'https://opencode.ai/zen/v1',
+        apiKey: 'sk-c5bkHCKoZ9VvSRkueeSmKzUE3YDJ2NOb50Rhyeb46l84ylc0JQuyFRUXJ2Gm7YdS',
+      })('big-pickle');
+    }
+
     // For Coder model, use Nvidia
     const { apiKey } = this.getProviderBaseUrlAndKey({
       apiKeys,