feat(kiro): add OAuth model name mappings support for Kiro

Add Kiro to the list of supported channels for OAuth model name mappings,
allowing users to map Kiro model IDs (e.g., kiro-claude-opus-4-5) to
canonical model names (e.g., claude-opus-4-5-20251101).

The Kiro case is implemented as a separate switch block to keep it
isolated from upstream CLIProxyAPI providers, making future merges
from the upstream repository cleaner.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sdk/cliproxy/auth/model_name_mappings.go

@@ -165,6 +165,8 @@ func OAuthModelMappingChannel(provider, authKind string) string {
 		return "codex"
 	case "gemini-cli", "aistudio", "antigravity", "qwen", "iflow":
 		return provider
+	case "kiro":
+		return provider
 	default:
 		return ""
 	}