Phase 0: add npm scripts — typecheck, test, and build entry points.

Vitest with passWithNoTests keeps CI green before test files land in later phases.

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -5,6 +5,11 @@
   "description": "Pi Coding Agent extension: re-inject skills after auto compaction",
   "type": "module",
   "license": "MIT",
+  "scripts": {
+    "typecheck": "tsc --noEmit",
+    "test": "vitest run --passWithNoTests",
+    "build": "npm run typecheck"
+  },
   "pi": {
     "extensions": [
       "./src/index.ts"
@@ -12,6 +17,7 @@
   },
   "devDependencies": {
     "@earendil-works/pi-coding-agent": "^0.79.6",
-    "typescript": "^5"
+    "typescript": "^5",
+    "vitest": "^3"
   }
 }