feat: expand slash-command goals from command templates

Resolves armed slash-command objectives from authoritative templates before dispatch
Applies OpenCode argument expansion for goal metadata in UI and scheduled tasks
Falls back to the raw invocation when command details are unavailable

packages/web/server/lib/openchamber-sessions/routes.test.js

@@ -361,6 +361,44 @@ describe('openchamber session routes', () => {
     }
   });
 
+  it('uses the expanded slash-command template as the goal objective before command dispatch', async () => {
+    const originalFetch = globalThis.fetch;
+    const createSessionGoal = vi.fn(async () => undefined);
+    commandListMock.mockResolvedValue({
+      data: [{
+        name: 'issue--to-pr',
+        template: 'Take $ARGUMENTS from issue through a verified pull request. Confirm the PR covers $ARGUMENTS.',
+      }],
+    });
+    globalThis.fetch = vi.fn();
+    try {
+      const { app } = createApp({ createSessionGoal });
+      const response = await request(app)
+        .post('/api/openchamber/sessions/ses_source/send')
+        .send({
+          directory: '/repo/app',
+          prompt: '/issue--to-pr LIN-123',
+          model: 'openai/gpt-5.5',
+          agent: 'build',
+          goal: true,
+        })
+        .expect(200);
+
+      expect(createSessionGoal).toHaveBeenCalledWith(expect.objectContaining({
+        objective: 'Take LIN-123 from issue through a verified pull request. Confirm the PR covers LIN-123.',
+      }));
+      expect(sessionCommandMock).toHaveBeenCalledWith(expect.objectContaining({
+        command: 'issue--to-pr',
+        arguments: 'LIN-123',
+      }));
+      expect(createSessionGoal.mock.invocationCallOrder[0]).toBeLessThan(sessionCommandMock.mock.invocationCallOrder[0]);
+      expect(response.body).toMatchObject({ goalEnabled: true, dispatchedAsCommand: true });
+      expect(globalThis.fetch).not.toHaveBeenCalled();
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+
   it('reuses the previous session selection when send omits model, agent, and variant', async () => {
     const originalFetch = globalThis.fetch;
     const fetchMock = vi.fn(async () => ({ ok: true, text: async () => '' }));