feat(api-key): add independent quota and expiration support

This feature allows API Keys to have their own quota limits and expiration
times, independent of the user's balance.

Backend:
- Add quota, quota_used, expires_at fields to api_key schema
- Implement IsExpired() and IsQuotaExhausted() checks in middleware
- Add ResetQuota and ClearExpiration API endpoints
- Integrate quota billing in gateway handlers (OpenAI, Anthropic, Gemini)
- Include quota/expiration fields in auth cache for performance
- Expiration check returns 403, quota exhausted returns 429

Frontend:
- Add quota and expiration inputs to key create/edit dialog
- Add quick-select buttons for expiration (+7, +30, +90 days)
- Add reset quota confirmation dialog
- Add expires_at column to keys list
- Add i18n translations for new features (en/zh)

Migration:
- Add 045_add_api_key_quota.sql for new columns

backend/ent/migrate/schema.go

@@ -20,6 +20,9 @@ var (
 		{Name: "status", Type: field.TypeString, Size: 20, Default: "active"},
 		{Name: "ip_whitelist", Type: field.TypeJSON, Nullable: true},
 		{Name: "ip_blacklist", Type: field.TypeJSON, Nullable: true},
+		{Name: "quota", Type: field.TypeFloat64, Default: 0, SchemaType: map[string]string{"postgres": "decimal(20,8)"}},
+		{Name: "quota_used", Type: field.TypeFloat64, Default: 0, SchemaType: map[string]string{"postgres": "decimal(20,8)"}},
+		{Name: "expires_at", Type: field.TypeTime, Nullable: true},
 		{Name: "group_id", Type: field.TypeInt64, Nullable: true},
 		{Name: "user_id", Type: field.TypeInt64},
 	}
@@ -31,13 +34,13 @@ var (
 		ForeignKeys: []*schema.ForeignKey{
 			{
 				Symbol:     "api_keys_groups_api_keys",
-				Columns:    []*schema.Column{APIKeysColumns[9]},
+				Columns:    []*schema.Column{APIKeysColumns[12]},
 				RefColumns: []*schema.Column{GroupsColumns[0]},
 				OnDelete:   schema.SetNull,
 			},
 			{
 				Symbol:     "api_keys_users_api_keys",
-				Columns:    []*schema.Column{APIKeysColumns[10]},
+				Columns:    []*schema.Column{APIKeysColumns[13]},
 				RefColumns: []*schema.Column{UsersColumns[0]},
 				OnDelete:   schema.NoAction,
 			},
@@ -46,12 +49,12 @@ var (
 			{
 				Name:    "apikey_user_id",
 				Unique:  false,
-				Columns: []*schema.Column{APIKeysColumns[10]},
+				Columns: []*schema.Column{APIKeysColumns[13]},
 			},
 			{
 				Name:    "apikey_group_id",
 				Unique:  false,
-				Columns: []*schema.Column{APIKeysColumns[9]},
+				Columns: []*schema.Column{APIKeysColumns[12]},
 			},
 			{
 				Name:    "apikey_status",
@@ -63,6 +66,16 @@ var (
 				Unique:  false,
 				Columns: []*schema.Column{APIKeysColumns[3]},
 			},
+			{
+				Name:    "apikey_quota_quota_used",
+				Unique:  false,
+				Columns: []*schema.Column{APIKeysColumns[9], APIKeysColumns[10]},
+			},
+			{
+				Name:    "apikey_expires_at",
+				Unique:  false,
+				Columns: []*schema.Column{APIKeysColumns[11]},
+			},
 		},
 	}
 	// AccountsColumns holds the columns for the "accounts" table.