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/tsconfig.json

@@ -13,10 +13,5 @@
       "@geo/ui-shared/tokens": ["../../packages/ui-shared/src/tokens/index.ts"]
     }
   },
-  "include": [
-    "electron.vite.config.ts",
-    "src/**/*.ts",
-    "src/**/*.d.ts",
-    "src/**/*.vue"
-  ]
+  "include": ["electron.vite.config.ts", "src/**/*.ts", "src/**/*.d.ts", "src/**/*.vue"]
 }