Fix duplicate session billing and align pricing with DeepSeek ×3.

Serialize billSessionUsage with row locks, expose rates on recharge, add compensation script and admin usage views.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/api/client.ts

@@ -41,6 +41,7 @@ import type {
   SessionEvent,
   SessionListResponse,
   UsageRecord,
+  UsageSummary,
   BalanceUpdate,
 } from '../types';
 
@@ -299,8 +300,14 @@ export async function getMe(): Promise<{
   return portalFetch('/auth/me');
 }
 
-export async function getMyUsage(): Promise<UsageRecord[]> {
-  const result = await portalFetch<{ records: UsageRecord[] }>('/auth/usage');
+export async function getMyUsageSummary(): Promise<UsageSummary> {
+  const result = await portalFetch<{ summary: UsageSummary }>('/auth/usage/summary');
+  return result.summary;
+}
+
+export async function getMyUsage(limit = 20): Promise<UsageRecord[]> {
+  const query = limit ? `?limit=${encodeURIComponent(String(limit))}` : '';
+  const result = await portalFetch<{ records: UsageRecord[] }>(`/auth/usage${query}`);
   return result.records ?? [];
 }
 
@@ -1010,8 +1017,19 @@ export async function getAdminDashboardSummary(): Promise<AdminDashboardSummary>
   return result.summary;
 }
 
-export async function listAdminUsage(userId?: string): Promise<UsageRecord[]> {
-  const query = userId ? `?userId=${encodeURIComponent(userId)}` : '';
+export async function getAdminUsageSummary(userId?: string): Promise<UsageSummary> {
+  const params = new URLSearchParams();
+  if (userId) params.set('userId', userId);
+  const query = params.toString() ? `?${params.toString()}` : '';
+  const result = await portalFetch<{ summary: UsageSummary }>(`/admin-api/usage/summary${query}`);
+  return result.summary;
+}
+
+export async function listAdminUsage(userId?: string, limit = 20): Promise<UsageRecord[]> {
+  const params = new URLSearchParams();
+  if (userId) params.set('userId', userId);
+  if (limit) params.set('limit', String(limit));
+  const query = params.toString() ? `?${params.toString()}` : '';
   const result = await portalFetch<{ records: UsageRecord[] }>(`/admin-api/usage${query}`);
   return result.records ?? [];
 }