Add Kimi (Moonshot AI) provider support

- OAuth2 device authorization grant flow (RFC 8628) for authentication
- Streaming and non-streaming chat completions via OpenAI-compatible API
- Models: kimi-k2, kimi-k2-thinking, kimi-k2.5
- CLI `--kimi-login` command for device flow auth
- Token management with automatic refresh
- Thinking/reasoning effort support for thinking-enabled models

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sdk/cliproxy/service.go

@@ -398,6 +398,8 @@ func (s *Service) ensureExecutorsForAuth(a *coreauth.Auth) {
 		s.coreManager.RegisterExecutor(executor.NewQwenExecutor(s.cfg))
 	case "iflow":
 		s.coreManager.RegisterExecutor(executor.NewIFlowExecutor(s.cfg))
+	case "kimi":
+		s.coreManager.RegisterExecutor(executor.NewKimiExecutor(s.cfg))
 	default:
 		providerKey := strings.ToLower(strings.TrimSpace(a.Provider))
 		if providerKey == "" {
@@ -799,6 +801,9 @@ func (s *Service) registerModelsForAuth(a *coreauth.Auth) {
 	case "iflow":
 		models = registry.GetIFlowModels()
 		models = applyExcludedModels(models, excluded)
+	case "kimi":
+		models = registry.GetKimiModels()
+		models = applyExcludedModels(models, excluded)
 	default:
 		// Handle OpenAI-compatibility providers by name using config
 		if s.cfg != nil {