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/desktop-client/src/main/playwright-cdp-targets.ts

@@ -1,29 +1,26 @@
 export interface CDPTargetDescriptor {
-  id?: string;
-  type?: string;
-  title?: string;
-  url?: string;
+  id?: string
+  type?: string
+  title?: string
+  url?: string
 }
 
-const hiddenPlaywrightTargetMarkers = [
-  "hidden-playwright",
-  "geo-hidden-playwright-token",
-] as const;
+const hiddenPlaywrightTargetMarkers = ['hidden-playwright', 'geo-hidden-playwright-token'] as const
 
 export function isReclaimableHiddenPlaywrightTarget(target: CDPTargetDescriptor): boolean {
-  if ((target.type ?? "").trim() !== "page") {
-    return false;
+  if ((target.type ?? '').trim() !== 'page') {
+    return false
   }
-  if (!(target.id ?? "").trim()) {
-    return false;
+  if (!(target.id ?? '').trim()) {
+    return false
   }
 
-  const title = target.title ?? "";
-  const url = target.url ?? "";
-  const haystack = `${title}\n${url}`.toLowerCase();
+  const title = target.title ?? ''
+  const url = target.url ?? ''
+  const haystack = `${title}\n${url}`.toLowerCase()
 
   // Blank Electron page targets can belong to visible BrowserWindow shells.
   // Only reclaim targets that we can prove were created by the hidden
   // Playwright bootstrap flow.
-  return hiddenPlaywrightTargetMarkers.some((marker) => haystack.includes(marker));
+  return hiddenPlaywrightTargetMarkers.some((marker) => haystack.includes(marker))
 }