feat(skills): add installer execution stub command

src/cli/skills.test.ts

@@ -15,6 +15,8 @@ import {
   renderSkillInstallerPlan,
   toSkillInstallPreflightView,
   renderSkillInstallPreflight,
+  toSkillInstallerExecutionStubView,
+  renderSkillInstallerExecutionStub,
 } from './skills.js';
 import type { Skill } from '../skills/index.js';
 
@@ -212,6 +214,39 @@ describe('skills CLI helpers', () => {
     expect(output).toContain('[download] download https://example.com/tool.tgz -> <default destination>');
   });
 
+  it('builds installer execution stub view from skill plan', () => {
+    const view = toSkillInstallerExecutionStubView(
+      buildSkill({
+        manifest: {
+          name: 'exec-stub',
+          description: 'Execution stub test',
+          version: '1.1.0',
+          tier: 'managed',
+          installers: [{ type: 'download', url: 'https://example.com/tool.tgz' }],
+        },
+      }),
+    );
+
+    expect(view.execution).toBe('stub');
+    expect(view.wouldRun.length).toBe(1);
+    expect(view.wouldRun[0]).toContain('download https://example.com/tool.tgz');
+  });
+
+  it('renders installer execution stub output text', () => {
+    const output = renderSkillInstallerExecutionStub({
+      skill: { name: 'exec-stub', tier: 'bundled', version: '1.0.0' },
+      execution: 'stub',
+      wouldRun: ['brew install jq'],
+      skipped: [{ installerType: 'node', reason: 'neither pnpm nor npm available in PATH' }],
+    });
+
+    expect(output).toContain("Installer execution stub for 'exec-stub'");
+    expect(output).toContain('No installer commands were executed.');
+    expect(output).toContain('Would run:');
+    expect(output).toContain('- brew install jq');
+    expect(output).toContain('Skipped:');
+  });
+
   it('summarizes refresh counts across status and tiers', () => {
     const summary = summarizeSkillsRefresh([
       buildSkill({ manifest: { name: 'a', description: 'a', version: '1.0.0', tier: 'bundled' } }),