feat: add testing using vitest

package.json

@@ -1,6 +1,6 @@
 {
   "name": "shsf-cli",
-  "version": "2.1.5",
+  "version": "2.1.6",
   "description": "",
   "type": "module",
   "files": [
@@ -12,7 +12,9 @@
   "scripts": {
     "build": "rimraf dist && tsc",
     "start": "node dist/index.js",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
   },
   "keywords": [],
   "author": "",
@@ -21,9 +23,11 @@
   "devDependencies": {
     "@types/inquirer": "^9.0.9",
     "@types/node": "^25.5.0",
+    "@vitest/coverage-v8": "^4.1.0",
     "rimraf": "^6.1.3",
     "ts-node": "^10.9.2",
-    "typescript": "^5.9.3"
+    "typescript": "^5.9.3",
+    "vitest": "^4.1.0"
   },
   "dependencies": {
     "axios": "^1.13.6",