fix: ix: antigravity 添加 aude-opus-4-6-thinking 模型支持

backend/internal/service/antigravity_gateway_service.go

@@ -304,6 +304,7 @@ func logPrefix(sessionID, accountName string) string {
 // Antigravity 直接支持的模型（精确匹配透传）
 // 注意：gemini-2.5 系列已移除，统一映射到 gemini-3 系列
 var antigravitySupportedModels = map[string]bool{
+	"claude-opus-4-6-thinking":   true,
 	"claude-opus-4-5-thinking":   true,
 	"claude-sonnet-4-5":          true,
 	"claude-sonnet-4-5-thinking": true,
@@ -337,6 +338,7 @@ var antigravityPrefixMapping = []struct {
 	{"claude-sonnet-4-5", "claude-sonnet-4-5"}, // claude-sonnet-4-5-xxx
 	{"claude-haiku-4-5", "claude-sonnet-4-5"},  // claude-haiku-4-5-xxx → sonnet
 	{"claude-opus-4-5", "claude-opus-4-5-thinking"},
+	{"claude-opus-4-6", "claude-opus-4-6-thinking"},
 	{"claude-3-haiku", "claude-sonnet-4-5"}, // 旧版 claude-3-haiku-xxx → sonnet
 	{"claude-sonnet-4", "claude-sonnet-4-5"},
 	{"claude-haiku-4", "claude-sonnet-4-5"}, // → sonnet