feat(cliproxy): add account quota display for Antigravity provider

- Add quota-fetcher.ts for Google Cloud Code API integration
- Add REST endpoint GET /api/cliproxy/quota/:provider/:accountId
- Add useAccountQuota hook with React Query caching
- Display quota bar in AccountItem with per-model tooltip
- Create reusable Progress component
- Consolidate quota types in api-client.ts

src/cliproxy/index.ts

@@ -111,6 +111,10 @@ export {
 export type { CliproxyStats } from './stats-fetcher';
 export { fetchCliproxyStats, isCliproxyRunning } from './stats-fetcher';
 
+// Quota fetcher
+export type { ModelQuota, QuotaResult } from './quota-fetcher';
+export { fetchAccountQuota } from './quota-fetcher';
+
 // OpenAI compatibility layer
 export type { OpenAICompatProvider, OpenAICompatModel } from './openai-compat-manager';
 export {