fix(design): preserve command outcome certainty

tests/unit/image-workspace-route.test.ts

@@ -3,7 +3,10 @@ import { Readable, Writable } from 'node:stream';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { handleImageWorkspaceRoutes } from '@electron/api/routes/image-workspace';
 import type { HostApiContext } from '@electron/api/context';
-import type { DesignWorkspaceModule } from '@electron/image-workspace/module';
+import {
+  DesignWorkspaceModuleError,
+  type DesignWorkspaceModule,
+} from '@electron/image-workspace/module';
 import {
   designBootstrapFixture,
   designWorkspaceFixture,
@@ -250,6 +253,37 @@ describe('AI design V2 Main route boundary', () => {
     expect(module.submitCommand).not.toHaveBeenCalled();
   });
 
+  it('preserves command outcome certainty in the local error envelope', async () => {
+    const module = moduleFixture({
+      submitCommand: vi.fn().mockRejectedValue(new DesignWorkspaceModuleError(
+        502,
+        'design_reasoner_invalid',
+        'AI 没有整理好这次想法，请再试一次',
+        'definitive_failure',
+      )),
+    });
+    const response = createResponse();
+
+    await handleImageWorkspaceRoutes(
+      createRequest('POST', {
+        kind: 'apply_input',
+        sessionId: 'session-1',
+        expectedDirectionRevision: 4,
+        clientOperationId: 'operation-1',
+        input: { kind: 'chat', message: '画一只会做饭的机器人' },
+      }),
+      response.res,
+      new URL('http://127.0.0.1/api/works/image-workspace/workspaces/workspace-1/commands'),
+      context(module),
+    );
+
+    expect(response.statusCode).toBe(502);
+    expect(response.json()).toMatchObject({
+      code: 'design_reasoner_invalid',
+      commandOutcome: 'definitive_failure',
+    });
+  });
+
   it('relays resumable normalized events over local SSE', async () => {
     const close = vi.fn();
     const openWorkspaceEvents = vi.fn().mockResolvedValue({