fix: SaaS Admin + Tauri 一致性审查修复

- 删除 webhook 死代码模块 (4 文件 + worker，未注册未挂载)
- 删除孤立组件 StatusTag.tsx (从未被导入)
- authStore 权限模型补全 (scheduler/knowledge/billing 6+ permission key)
- authStore 硬编码 logout URL 改为 env 变量
- 清理未使用 service 方法 (agent-templates/billing/roles)
- Logs.tsx 代码重复消除 (本地常量 → @/constants/status)
- TRUTH.md 数字校准 (Tauri 177→183, SaaS API 131→130)

admin-v2/src/services/billing.ts

@@ -80,18 +80,10 @@ export const billingService = {
     request.get<BillingPlan[]>('/billing/plans', withSignal({}, signal))
       .then((r) => r.data),
 
-  getPlan: (id: string, signal?: AbortSignal) =>
-    request.get<BillingPlan>(`/billing/plans/${id}`, withSignal({}, signal))
-      .then((r) => r.data),
-
   getSubscription: (signal?: AbortSignal) =>
     request.get<SubscriptionInfo>('/billing/subscription', withSignal({}, signal))
       .then((r) => r.data),
 
-  getUsage: (signal?: AbortSignal) =>
-    request.get<UsageQuota>('/billing/usage', withSignal({}, signal))
-      .then((r) => r.data),
-
   createPayment: (data: { plan_id: string; payment_method: 'alipay' | 'wechat' }) =>
     request.post<PaymentResult>('/billing/payments', data).then((r) => r.data),