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/types/index.ts

@@ -279,6 +279,8 @@ export interface ApiKey {
   name: string
   group_id: number | null
   status: 'active' | 'inactive'
+  ip_whitelist: string[]
+  ip_blacklist: string[]
   created_at: string
   updated_at: string
   group?: Group
@@ -288,12 +290,16 @@ export interface CreateApiKeyRequest {
   name: string
   group_id?: number | null
   custom_key?: string // Optional custom API Key
+  ip_whitelist?: string[]
+  ip_blacklist?: string[]
 }
 
 export interface UpdateApiKeyRequest {
   name?: string
   group_id?: number | null
   status?: 'active' | 'inactive'
+  ip_whitelist?: string[]
+  ip_blacklist?: string[]
 }
 
 export interface CreateGroupRequest {
@@ -560,9 +566,6 @@ export interface UpdateProxyRequest {
 
 export type RedeemCodeType = 'balance' | 'concurrency' | 'subscription'
 
-// 消费类型: 0=钱包余额, 1=订阅套餐
-export type BillingType = 0 | 1
-
 export interface UsageLog {
   id: number
   user_id: number
@@ -589,7 +592,6 @@ export interface UsageLog {
   actual_cost: number
   rate_multiplier: number
 
-  billing_type: BillingType
   stream: boolean
   duration_ms: number
   first_token_ms: number | null
@@ -601,6 +603,9 @@ export interface UsageLog {
   // User-Agent
   user_agent: string | null
 
+  // IP 地址（仅管理员可见）
+  ip_address: string | null
+
   created_at: string
 
   user?: User
@@ -830,7 +835,6 @@ export interface UsageQueryParams {
   group_id?: number
   model?: string
   stream?: boolean
-  billing_type?: number
   start_date?: string
   end_date?: string
 }