feat: add /convert-to-apple-container skill, remove /convert-to-docker (#324)

Docker is now the default runtime. The /convert-to-apple-container skill
uses the new skills engine format (manifest.yaml, modify/, intent files,
tests/) to switch to Apple Container on macOS.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.claude/skills/convert-to-apple-container/tests/convert-to-apple-container.test.ts

@@ -0,0 +1,69 @@
+import { describe, expect, it } from 'vitest';
+import fs from 'fs';
+import path from 'path';
+
+describe('convert-to-apple-container skill package', () => {
+  const skillDir = path.resolve(__dirname, '..');
+
+  it('has a valid manifest', () => {
+    const manifestPath = path.join(skillDir, 'manifest.yaml');
+    expect(fs.existsSync(manifestPath)).toBe(true);
+
+    const content = fs.readFileSync(manifestPath, 'utf-8');
+    expect(content).toContain('skill: convert-to-apple-container');
+    expect(content).toContain('version: 1.0.0');
+    expect(content).toContain('container-runtime.ts');
+    expect(content).toContain('container/build.sh');
+  });
+
+  it('has all modified files', () => {
+    const runtimeFile = path.join(skillDir, 'modify', 'src', 'container-runtime.ts');
+    expect(fs.existsSync(runtimeFile)).toBe(true);
+
+    const content = fs.readFileSync(runtimeFile, 'utf-8');
+    expect(content).toContain("CONTAINER_RUNTIME_BIN = 'container'");
+    expect(content).toContain('system status');
+    expect(content).toContain('system start');
+    expect(content).toContain('ls --format json');
+
+    const testFile = path.join(skillDir, 'modify', 'src', 'container-runtime.test.ts');
+    expect(fs.existsSync(testFile)).toBe(true);
+
+    const testContent = fs.readFileSync(testFile, 'utf-8');
+    expect(testContent).toContain('system status');
+    expect(testContent).toContain('--mount');
+  });
+
+  it('has intent files for modified sources', () => {
+    const runtimeIntent = path.join(skillDir, 'modify', 'src', 'container-runtime.ts.intent.md');
+    expect(fs.existsSync(runtimeIntent)).toBe(true);
+
+    const buildIntent = path.join(skillDir, 'modify', 'container', 'build.sh.intent.md');
+    expect(fs.existsSync(buildIntent)).toBe(true);
+  });
+
+  it('has build.sh with Apple Container default', () => {
+    const buildFile = path.join(skillDir, 'modify', 'container', 'build.sh');
+    expect(fs.existsSync(buildFile)).toBe(true);
+
+    const content = fs.readFileSync(buildFile, 'utf-8');
+    expect(content).toContain('CONTAINER_RUNTIME:-container');
+    expect(content).not.toContain('CONTAINER_RUNTIME:-docker');
+  });
+
+  it('uses Apple Container API patterns (not Docker)', () => {
+    const runtimeFile = path.join(skillDir, 'modify', 'src', 'container-runtime.ts');
+    const content = fs.readFileSync(runtimeFile, 'utf-8');
+
+    // Apple Container patterns
+    expect(content).toContain('system status');
+    expect(content).toContain('system start');
+    expect(content).toContain('ls --format json');
+    expect(content).toContain('type=bind,source=');
+
+    // Should NOT contain Docker patterns
+    expect(content).not.toContain('docker info');
+    expect(content).not.toContain("'-v'");
+    expect(content).not.toContain('--filter name=');
+  });
+});