v0.5.2 — Add ESLint + typescript-eslint, fix lint errors

Add flat-config ESLint with typescript-eslint recommended rules,
fix all lint errors (unused imports/vars, empty catches, Function types,
prefer-const, useless assignments), and rename stale kpc- CSS class to kcc-.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "krunker-civilian-client",
-  "version": "0.5.1",
+  "version": "0.5.2",
   "description": "Cross-platform Krunker game client",
   "main": "dist/main/index.js",
   "homepage": "https://gitea.crjlab.net/bigjakk/krunker-civilian-client",
@@ -17,18 +17,22 @@
     "dist:win": "npm run build && electron-builder --win",
     "dist:linux": "npm run build && electron-builder --linux",
     "dist:all": "npm run build && electron-builder --win --linux",
-    "clean": "rimraf dist out"
+    "clean": "rimraf dist out",
+    "lint": "eslint src/"
   },
   "dependencies": {
     "electron-store": "^8.2.0",
     "uuid": "^9.0.1"
   },
   "devDependencies": {
+    "@eslint/js": "^10.0.1",
     "@types/node": "^22.0.0",
     "electron": "npm:electron-nightly@42.0.0-nightly.20260227",
     "electron-builder": "^26.0.0",
+    "eslint": "^10.0.2",
     "rimraf": "^6.0.1",
     "typescript": "^5.7.0",
+    "typescript-eslint": "^8.56.1",
     "vite": "^6.0.0"
   }
 }