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/ops-web/src/styles.css

@@ -6,8 +6,15 @@ body,
 }
 
 body {
-  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
-    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
+  font-family:
+    'Inter',
+    -apple-system,
+    BlinkMacSystemFont,
+    'Segoe UI',
+    'PingFang SC',
+    'Hiragino Sans GB',
+    'Microsoft YaHei',
+    sans-serif;
   background-color: #f8fafc; /* Lighter, cooler gray */
   color: #334155;
 }
@@ -28,7 +35,9 @@ body {
 .ops-card {
   background: #ffffff;
   border-radius: 12px;
-  box-shadow: 0 1px 3px 0 rgba(15, 23, 42, 0.08), 0 1px 2px -1px rgba(15, 23, 42, 0.04);
+  box-shadow:
+    0 1px 3px 0 rgba(15, 23, 42, 0.08),
+    0 1px 2px -1px rgba(15, 23, 42, 0.04);
   padding: 24px;
   border: 1px solid #f1f5f9;
 }