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.

backend/internal/repository/usage_log_repo.go

@@ -22,7 +22,7 @@ import (
 	"github.com/lib/pq"
 )
 
-const usageLogSelectColumns = "id, user_id, api_key_id, account_id, request_id, model, group_id, subscription_id, input_tokens, output_tokens, cache_creation_tokens, cache_read_tokens, cache_creation_5m_tokens, cache_creation_1h_tokens, input_cost, output_cost, cache_creation_cost, cache_read_cost, total_cost, actual_cost, rate_multiplier, billing_type, stream, duration_ms, first_token_ms, user_agent, image_count, image_size, created_at"
+const usageLogSelectColumns = "id, user_id, api_key_id, account_id, request_id, model, group_id, subscription_id, input_tokens, output_tokens, cache_creation_tokens, cache_read_tokens, cache_creation_5m_tokens, cache_creation_1h_tokens, input_cost, output_cost, cache_creation_cost, cache_read_cost, total_cost, actual_cost, rate_multiplier, billing_type, stream, duration_ms, first_token_ms, user_agent, ip_address, image_count, image_size, created_at"
 
 type usageLogRepository struct {
 	client *dbent.Client
@@ -110,6 +110,7 @@ func (r *usageLogRepository) Create(ctx context.Context, log *service.UsageLog)
 			duration_ms,
 			first_token_ms,
 			user_agent,
+			ip_address,
 			image_count,
 			image_size,
 			created_at
@@ -119,7 +120,7 @@ func (r *usageLogRepository) Create(ctx context.Context, log *service.UsageLog)
 			$8, $9, $10, $11,
 			$12, $13,
 			$14, $15, $16, $17, $18, $19,
-		$20, $21, $22, $23, $24, $25, $26, $27, $28
+			$20, $21, $22, $23, $24, $25, $26, $27, $28, $29
 		)
 		ON CONFLICT (request_id, api_key_id) DO NOTHING
 		RETURNING id, created_at
@@ -130,6 +131,7 @@ func (r *usageLogRepository) Create(ctx context.Context, log *service.UsageLog)
 	duration := nullInt(log.DurationMs)
 	firstToken := nullInt(log.FirstTokenMs)
 	userAgent := nullString(log.UserAgent)
+	ipAddress := nullString(log.IPAddress)
 	imageSize := nullString(log.ImageSize)
 
 	var requestIDArg any
@@ -163,6 +165,7 @@ func (r *usageLogRepository) Create(ctx context.Context, log *service.UsageLog)
 		duration,
 		firstToken,
 		userAgent,
+		ipAddress,
 		log.ImageCount,
 		imageSize,
 		createdAt,
@@ -1873,6 +1876,7 @@ func scanUsageLog(scanner interface{ Scan(...any) error }) (*service.UsageLog, e
 		durationMs          sql.NullInt64
 		firstTokenMs        sql.NullInt64
 		userAgent           sql.NullString
+		ipAddress           sql.NullString
 		imageCount          int
 		imageSize           sql.NullString
 		createdAt           time.Time
@@ -1905,6 +1909,7 @@ func scanUsageLog(scanner interface{ Scan(...any) error }) (*service.UsageLog, e
 		&durationMs,
 		&firstTokenMs,
 		&userAgent,
+		&ipAddress,
 		&imageCount,
 		&imageSize,
 		&createdAt,
@@ -1959,6 +1964,9 @@ func scanUsageLog(scanner interface{ Scan(...any) error }) (*service.UsageLog, e
 	if userAgent.Valid {
 		log.UserAgent = &userAgent.String
 	}
+	if ipAddress.Valid {
+		log.IPAddress = &ipAddress.String
+	}
 	if imageSize.Valid {
 		log.ImageSize = &imageSize.String
 	}