chore(frontend): introduce prettier + eslint and prune unused code

- Add Prettier 3 with prettier-plugin-organize-imports (sorts/removes unused imports)
- Add ESLint 10 flat config with typescript-eslint + eslint-plugin-vue + eslint-config-prettier
- Add root scripts: format, format:check, lint, lint:fix
- Reformat 257 files across admin-web, ops-web, desktop-client, packages
- Remove unused locals/exports flagged by --noUnusedLocals/--noUnusedParameters
- Fix duplicate localTabLabel key, surrogate-pair regex u-flag, NBSP literal in regex
- Skip server/ (Go) and apps/browser-extension/ (deprecated per ADR)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/admin-web/src/router/meta.d.ts

@@ -1,15 +1,15 @@
-import "vue-router";
+import 'vue-router'
 
-declare module "vue-router" {
+declare module 'vue-router' {
   interface RouteMeta {
-    title?: string;
-    description?: string;
-    titleKey?: string;
-    descriptionKey?: string;
-    requiresAuth?: boolean;
-    requiresKol?: boolean;
-    navKey?: string | null;
+    title?: string
+    description?: string
+    titleKey?: string
+    descriptionKey?: string
+    requiresAuth?: boolean
+    requiresKol?: boolean
+    navKey?: string | null
   }
 }
 
-export {};
+export {}