feat: per-account quota threshold protection (#212)

feat: per-account quota threshold protection

Resolves #135

- Adds configurable quota protection with three-tier threshold resolution (per-model → per-account → global)
- New global Minimum Quota Level slider in Settings
- Per-account threshold settings via Account Settings modal
- Draggable per-account threshold markers on model quota bars
- Backend: PATCH /api/accounts/:email endpoint, globalQuotaThreshold config
- i18n: quota protection keys for all 5 languages

src/account-manager/index.js

@@ -5,6 +5,7 @@
  */
 
 import { ACCOUNT_CONFIG_PATH } from '../constants.js';
+import { config } from '../config.js';
 import { loadAccounts, loadDefaultAccount, saveAccounts } from './storage.js';
 import {
     isAllRateLimited as checkAllRateLimited,
@@ -33,7 +34,6 @@ import {
 } from './credentials.js';
 import { createStrategy, getStrategyLabel, DEFAULT_STRATEGY } from './strategies/index.js';
 import { logger } from '../utils/logger.js';
-import { config } from '../config.js';
 
 export class AccountManager {
     #accounts = [];
@@ -433,7 +433,10 @@ export class AccountManager {
                 modelRateLimits: a.modelRateLimits || {},
                 isInvalid: a.isInvalid || false,
                 invalidReason: a.invalidReason || null,
-                lastUsed: a.lastUsed
+                lastUsed: a.lastUsed,
+                // Include quota threshold settings
+                quotaThreshold: a.quotaThreshold,
+                modelQuotaThresholds: a.modelQuotaThresholds || {}
             }))
         };
     }