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/tracing/recorder.ts

@@ -1,7 +1,7 @@
 export interface TraceRecord {
-  type: string;
-  createdAt: number;
-  payload: Record<string, unknown>;
+  type: string
+  createdAt: number
+  payload: Record<string, unknown>
 }
 
 export function createTraceRecord(type: string, payload: Record<string, unknown>): TraceRecord {
@@ -9,5 +9,5 @@ export function createTraceRecord(type: string, payload: Record<string, unknown>
     type,
     createdAt: Date.now(),
     payload,
-  };
+  }
 }

apps/desktop-client/src/main/tracing/redactor.ts

@@ -1,10 +1,10 @@
-const redactKeys = new Set(["authorization", "cookie", "password", "token"]);
+const redactKeys = new Set(['authorization', 'cookie', 'password', 'token'])
 
 export function redactPayload(payload: Record<string, unknown>): Record<string, unknown> {
   return Object.fromEntries(
     Object.entries(payload).map(([key, value]) => [
       key,
-      redactKeys.has(key.toLowerCase()) ? "[REDACTED]" : value,
+      redactKeys.has(key.toLowerCase()) ? '[REDACTED]' : value,
     ]),
-  );
+  )
 }

apps/desktop-client/src/main/tracing/trace-writer.ts

@@ -1,5 +1,5 @@
-import type { TraceRecord } from "./recorder";
+import type { TraceRecord } from './recorder'
 
 export function serializeTrace(records: TraceRecord[]): string {
-  return JSON.stringify(records, null, 2);
+  return JSON.stringify(records, null, 2)
 }