fix(review): address Copilot comments and fix CI build failure

- Copilot-instructions.md precedence: prefer .github/ path, do not
  load both when both exist
- Simplify getModel() call: remove unnecessary typeof guard since
  Config already defines getModel()
- Fix TS2352 type error in test: use proper mock cast pattern
- Add getModel to base mockConfig for test consistency

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/cli/src/services/BundledSkillLoader.test.ts

@@ -34,6 +34,7 @@ describe('BundledSkillLoader', () => {
     mockConfig = {
       getSkillManager: vi.fn().mockReturnValue(mockSkillManager),
       isCronEnabled: vi.fn().mockReturnValue(false),
+      getModel: vi.fn().mockReturnValue(undefined),
     } as unknown as Config;
   });
 
@@ -132,9 +133,9 @@ describe('BundledSkillLoader', () => {
       body: 'Review by {{model}} via Qwen Code',
     });
     mockSkillManager.listSkills.mockResolvedValue([skill]);
-    (mockConfig as Record<string, unknown>).getModel = vi
-      .fn()
-      .mockReturnValue('qwen3-coder');
+    (mockConfig.getModel as ReturnType<typeof vi.fn>).mockReturnValue(
+      'qwen3-coder',
+    );
 
     const loader = new BundledSkillLoader(mockConfig);
     const commands = await loader.loadCommands(signal);