feat(quota): add tunnel traffic quota with daily/monthly limits (#291) (#308)

Implement per-tunnel traffic quota feature:
- Add TunnelQuota model with daily/monthly usage tracking
- Integrate quota enforcement into flow accumulation path
- Pause forwards and disable tunnel when quota exceeded
- Block new forward creation/resume when tunnel quota disabled
- Auto-reset daily/monthly windows at 00:05 via maintenance job
- Add manual reset API endpoint for admins
- Include quota config in tunnel backup/restore
- Add frontend UI for quota settings and usage display

Entire-Checkpoint: e629b27ca437

vite-frontend/src/pages/tunnel/form.ts

@@ -8,6 +8,8 @@ interface TunnelFormInput {
   inNodeId: TunnelChainNode[];
   outNodeId?: TunnelChainNode[];
   trafficRatio: number;
+  dailyQuotaGB?: number;
+  monthlyQuotaGB?: number;
 }
 
 interface TunnelNodeInput {
@@ -24,6 +26,8 @@ export const createTunnelFormDefaults = () => {
     chainNodes: [],
     flow: 1,
     trafficRatio: 1.0,
+    dailyQuotaGB: 0,
+    monthlyQuotaGB: 0,
     inIp: "",
     ipPreference: "",
     status: 1,
@@ -60,6 +64,14 @@ export const validateTunnelForm = (
     errors.trafficRatio = "流量倍率须大于0，支持小数（如 0.5）";
   }
 
+  if ((form.dailyQuotaGB ?? 0) < 0) {
+    errors.dailyQuotaGB = "每日配额不能小于 0";
+  }
+
+  if ((form.monthlyQuotaGB ?? 0) < 0) {
+    errors.monthlyQuotaGB = "每月配额不能小于 0";
+  }
+
   if (form.type === 2) {
     if (!form.outNodeId || form.outNodeId.length === 0) {
       errors.outNodeId = "请至少选择一个出口节点";