Fix action runtime by bundling dependencies with ncc

The action was failing with "Cannot find module '@actions/core'" because
node_modules weren't available at runtime. This commit fixes the issue by:

- Adding @vercel/ncc to bundle all dependencies into a single dist/index.js file
- Updating action.yml to point to the bundled dist/index.js
- Adding a build script to compile the action
- Including the dist/ directory in the repository (standard for GitHub Actions)

This is the recommended approach for JavaScript-based GitHub Actions to ensure
all dependencies are available at runtime without requiring npm install.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.gitignore

@@ -11,4 +11,7 @@ example/example
 *.exe
 *.dll
 *.so
-*.dylib
+*.dylib
+
+# Don't ignore the compiled output
+!dist/

action.yml

@@ -16,4 +16,4 @@ outputs:
 
 runs:
   using: 'node20'
-  main: 'index.js'
+  main: 'dist/index.js'

package-lock.json

@@ -14,6 +14,7 @@
         "@actions/github": "^6.0.0"
       },
       "devDependencies": {
+        "@vercel/ncc": "^0.38.1",
         "jest": "^29.7.0"
       }
     },
@@ -1249,6 +1250,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@vercel/ncc": {
+      "version": "0.38.3",
+      "resolved": "https://registry.npmjs.org/@vercel/ncc/-/ncc-0.38.3.tgz",
+      "integrity": "sha512-rnK6hJBS6mwc+Bkab+PGPs9OiS0i/3kdTO+CkI8V0/VrW3vmz7O2Pxjw/owOlmo6PKEIxRSeZKv/kuL9itnpYA==",
+      "dev": true,
+      "license": "MIT",
+      "bin": {
+        "ncc": "dist/ncc/cli.js"
+      }
+    },
     "node_modules/ansi-escapes": {
       "version": "4.3.2",
       "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-4.3.2.tgz",

package.json

@@ -4,6 +4,7 @@
   "description": "A minimal GitHub Action implemented in Node.js",
   "main": "index.js",
   "scripts": {
+    "build": "ncc build index.js -o dist",
     "test": "jest",
     "test:watch": "jest --watch",
     "test:coverage": "jest --coverage"
@@ -20,7 +21,8 @@
     "@actions/exec": "^1.1.1"
   },
   "devDependencies": {
-    "jest": "^29.7.0"
+    "jest": "^29.7.0",
+    "@vercel/ncc": "^0.38.1"
   },
   "jest": {
     "testEnvironment": "node",