feat: service route branch handling, workspace hover card redesign, and agent form state improvements

- Add service-route-branch-handler for routing requests to branch-specific services
- Add service-hostname utility for generating hostnames from branch names
- Redesign workspace hover card with CI check status display
- Update combined model selector and sidebar workspace list
- Improve agent form state and input draft hooks
- Update checkout-git with enhanced branch handling
- Add workspace git watch and bootstrap improvements

packages/app/src/hooks/use-agent-form-state.ts

@@ -138,7 +138,7 @@ function resolveEffectiveModel(
   }
   const normalizedModelId = modelId.trim();
   if (!normalizedModelId) {
-    return resolveDefaultModel(availableModels);
+    return null;
   }
   return (
     availableModels.find((model) => model.id === normalizedModelId) ??
@@ -243,8 +243,6 @@ function resolveFormState(
       } else {
         result.model = defaultModelId;
       }
-    } else if (defaultModelId) {
-      result.model = defaultModelId;
     } else {
       result.model = "";
     }