feat(api-key): 添加 IP 白名单/黑名单限制功能 (#221)

* feat(api-key): add IP whitelist/blacklist restriction and usage log IP tracking

- Add IP restriction feature for API keys (whitelist/blacklist with CIDR support)
- Add IP address logging to usage logs (admin-only visibility)
- Remove billing_type column from usage logs UI (redundant)
- Use generic "Access denied" error message for security

Backend:
- New ip package with IP/CIDR validation and matching utilities
- Database migrations for ip_whitelist, ip_blacklist (api_keys) and ip_address (usage_logs)
- Middleware IP restriction check after API key validation
- Input validation for IP/CIDR patterns on create/update

Frontend:
- API key form with enable toggle for IP restriction
- Shield icon indicator in table for keys with IP restriction
- Removed billing_type filter and column from usage views

* fix: update API contract tests for ip_whitelist/ip_blacklist fields

Add ip_whitelist and ip_blacklist fields to expected JSON responses
in API contract tests to match the new API key schema.

frontend/src/api/admin/usage.ts

@@ -64,7 +64,6 @@ export async function getStats(params: {
   group_id?: number
   model?: string
   stream?: boolean
-  billing_type?: number
   period?: string
   start_date?: string
   end_date?: string

frontend/src/api/keys.ts

@@ -42,12 +42,16 @@ export async function getById(id: number): Promise<ApiKey> {
  * @param name - Key name
  * @param groupId - Optional group ID
  * @param customKey - Optional custom key value
+ * @param ipWhitelist - Optional IP whitelist
+ * @param ipBlacklist - Optional IP blacklist
  * @returns Created API key
  */
 export async function create(
   name: string,
   groupId?: number | null,
-  customKey?: string
+  customKey?: string,
+  ipWhitelist?: string[],
+  ipBlacklist?: string[]
 ): Promise<ApiKey> {
   const payload: CreateApiKeyRequest = { name }
   if (groupId !== undefined) {
@@ -56,6 +60,12 @@ export async function create(
   if (customKey) {
     payload.custom_key = customKey
   }
+  if (ipWhitelist && ipWhitelist.length > 0) {
+    payload.ip_whitelist = ipWhitelist
+  }
+  if (ipBlacklist && ipBlacklist.length > 0) {
+    payload.ip_blacklist = ipBlacklist
+  }
 
   const { data } = await apiClient.post<ApiKey>('/keys', payload)
   return data