feat: add quota limit for API key accounts

- Add configurable spending limit (quota_limit) for apikey-type accounts
- Atomic quota accumulation via PostgreSQL JSONB operations on TotalCost
- Scheduler filters out over-quota accounts with outbox-triggered snapshot refresh
- Display quota usage ($used / $limit) in account capacity column
- Add "Reset Quota" action in account menu to reset usage to zero
- Editing account settings preserves quota_used (no accidental reset)
- Covers all 3 billing paths: Anthropic, Gemini, OpenAI RecordUsage

chore: bump version to 0.1.90.4

backend/internal/repository/account_repo.go

@@ -1657,3 +1657,60 @@ func (r *accountRepository) FindByExtraField(ctx context.Context, key string, va
 
 	return r.accountsToService(ctx, accounts)
 }
+
+// IncrementQuotaUsed 原子递增账号的 extra.quota_used 字段
+func (r *accountRepository) IncrementQuotaUsed(ctx context.Context, id int64, amount float64) error {
+	rows, err := r.sql.QueryContext(ctx,
+		`UPDATE accounts SET extra = jsonb_set(
+			COALESCE(extra, '{}'::jsonb),
+			'{quota_used}',
+			to_jsonb(COALESCE((extra->>'quota_used')::numeric, 0) + $1)
+		), updated_at = NOW()
+		WHERE id = $2 AND deleted_at IS NULL
+		RETURNING
+			COALESCE((extra->>'quota_used')::numeric, 0),
+			COALESCE((extra->>'quota_limit')::numeric, 0)`,
+		amount, id)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = rows.Close() }()
+
+	var newUsed, limit float64
+	if rows.Next() {
+		if err := rows.Scan(&newUsed, &limit); err != nil {
+			return err
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return err
+	}
+
+	// 配额刚超限时触发调度快照刷新，使账号及时从调度候选中移除
+	if limit > 0 && newUsed >= limit && (newUsed-amount) < limit {
+		if err := enqueueSchedulerOutbox(ctx, r.sql, service.SchedulerOutboxEventAccountChanged, &id, nil, nil); err != nil {
+			logger.LegacyPrintf("repository.account", "[SchedulerOutbox] enqueue quota exceeded failed: account=%d err=%v", id, err)
+		}
+	}
+	return nil
+}
+
+// ResetQuotaUsed 重置账号的 extra.quota_used 为 0
+func (r *accountRepository) ResetQuotaUsed(ctx context.Context, id int64) error {
+	_, err := r.sql.ExecContext(ctx,
+		`UPDATE accounts SET extra = jsonb_set(
+			COALESCE(extra, '{}'::jsonb),
+			'{quota_used}',
+			'0'::jsonb
+		), updated_at = NOW()
+		WHERE id = $1 AND deleted_at IS NULL`,
+		id)
+	if err != nil {
+		return err
+	}
+	// 重置配额后触发调度快照刷新，使账号重新参与调度
+	if err := enqueueSchedulerOutbox(ctx, r.sql, service.SchedulerOutboxEventAccountChanged, &id, nil, nil); err != nil {
+		logger.LegacyPrintf("repository.account", "[SchedulerOutbox] enqueue quota reset failed: account=%d err=%v", id, err)
+	}
+	return nil
+}