Add unit tests for root action.yml correctness

Tests verify: correct main path, node20 runtime, and that inputs/outputs
stay in sync with packages/action/action.yml to prevent drift.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: DeDuckProject

package.json

@@ -18,8 +18,10 @@
     "lint": "pnpm -r lint"
   },
   "devDependencies": {
+    "@types/js-yaml": "^4.0.9",
+    "@types/node": "^20.12.0",
+    "js-yaml": "^4.1.1",
     "typescript": "^5.4.5",
-    "vitest": "^1.6.0",
-    "@types/node": "^20.12.0"
+    "vitest": "^1.6.0"
   }
 }

pnpm-lock.yaml

@@ -0,0 +1,39 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'fs';
+import { resolve } from 'path';
+import { load } from 'js-yaml';
+
+const root = resolve(__dirname, '../..');
+
+function loadActionYml(path: string): any {
+  return load(readFileSync(path, 'utf8'));
+}
+
+describe('root action.yml', () => {
+  const rootAction = loadActionYml(resolve(root, 'action.yml'));
+  const pkgAction = loadActionYml(resolve(root, 'packages/action/action.yml'));
+
+  it('points main to packages/action/dist/index.js', () => {
+    expect(rootAction.runs.main).toBe('packages/action/dist/index.js');
+  });
+
+  it('uses node20 runtime', () => {
+    expect(rootAction.runs.using).toBe('node20');
+  });
+
+  it('has the same inputs as packages/action/action.yml', () => {
+    expect(Object.keys(rootAction.inputs ?? {})).toEqual(
+      Object.keys(pkgAction.inputs ?? {})
+    );
+  });
+
+  it('has the same outputs as packages/action/action.yml', () => {
+    expect(Object.keys(rootAction.outputs ?? {})).toEqual(
+      Object.keys(pkgAction.outputs ?? {})
+    );
+  });
+
+  it('packages/action/action.yml still uses relative dist path', () => {
+    expect(pkgAction.runs.main).toBe('dist/index.js');
+  });
+});