pl-api: initialize tests

Signed-off-by: nicole mikołajczyk <git@mkljczk.pl>

packages/pl-api/package.json

@@ -24,7 +24,10 @@
     "lint": "oxlint",
     "fmt": "oxfmt",
     "fmt:check": "oxfmt --check",
-    "precommit": "lint-staged"
+    "precommit": "lint-staged",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
   },
   "dependencies": {
     "blurhash": "^2.0.5",
@@ -39,6 +42,7 @@
     "@types/http-link-header": "^1.0.7",
     "@types/node": "^25.3.0",
     "@types/semver": "^7.7.1",
+    "@vitest/coverage-v8": "4.0.18",
     "oxfmt": "^0.35.0",
     "oxlint": "^1.50.0",
     "typedoc": "^0.28.17",
@@ -47,6 +51,7 @@
     "typescript": "^5.9.3",
     "vite": "^7.3.1",
     "vite-plugin-dts": "^4.5.4",
+    "vitest": "^4.0.18",
     "ws": "^8.19.0"
   },
   "lint-staged": {