Add frontend package-lock.json for npm ci support

frontend/package-lock.json

@@ -0,0 +1,20 @@
+{
+  "name": "png-editor-frontend",
+  "version": "0.1.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "png-editor-frontend",
+      "version": "0.1.0",
+      "devDependencies": {
+        "@sveltejs/vite-plugin-svelte": "^3.0.0",
+        "svelte": "^4.2.0",
+        "svelte-check": "^4.0.0",
+        "svelte-preprocess": "^6.0.0",
+        "typescript": "^5.6.0",
+        "vite": "^5.0.0"
+      }
+    }
+  }
+}