feat(chat): migration 0004 + errs codes for chat/llm/storage

internal/infra/errs/errs.go

@@ -44,6 +44,28 @@ const (
 	CodeWorktreePathInvalid     Code = "worktree_path_invalid"
 	CodeGitCredentialInvalid    Code = "git_credential_invalid"
 	CodeGitCmdFailed            Code = "git_cmd_failed"
+
+	// Chat 模块
+	CodeChatConversationNotFound      Code = "chat.conversation_not_found"
+	CodeChatMessageNotFound           Code = "chat.message_not_found"
+	CodeChatMessageNotPending         Code = "chat.message_not_pending"
+	CodeChatConcurrentMessage         Code = "chat.concurrent_message"
+	CodeChatAttachmentTooLarge        Code = "chat.attachment_too_large"
+	CodeChatAttachmentUnsupportedMime Code = "chat.attachment_unsupported_mime"
+	CodeChatModelCapabilityMismatch   Code = "chat.model_capability_mismatch"
+	CodeChatTemplateNotFound          Code = "chat.template_not_found"
+	CodeChatEndpointNotFound          Code = "chat.endpoint_not_found"
+	CodeChatModelNotFound             Code = "chat.model_not_found"
+
+	// LLM 域
+	CodeLLMUpstream       Code = "llm.upstream_error"
+	CodeLLMTimeout        Code = "llm.timeout"
+	CodeLLMRateLimited    Code = "llm.rate_limited"
+	CodeLLMContextTooLong Code = "llm.context_too_long"
+
+	// Storage 域
+	CodeStoragePutFailed Code = "storage.put_failed"
+	CodeStorageGetFailed Code = "storage.get_failed"
 )
 
 // AppError is the application's structured error type. It carries a stable
@@ -131,6 +153,24 @@ func HTTPStatus(code Code) int {
 		return http.StatusBadRequest
 	case CodeWorktreeNotHeldByCaller:
 		return http.StatusForbidden
+	case CodeChatConversationNotFound, CodeChatMessageNotFound,
+		CodeChatTemplateNotFound, CodeChatEndpointNotFound, CodeChatModelNotFound:
+		return http.StatusNotFound
+	case CodeChatMessageNotPending, CodeChatConcurrentMessage,
+		CodeChatModelCapabilityMismatch:
+		return http.StatusConflict
+	case CodeChatAttachmentTooLarge:
+		return http.StatusRequestEntityTooLarge
+	case CodeChatAttachmentUnsupportedMime:
+		return http.StatusUnsupportedMediaType
+	case CodeLLMRateLimited:
+		return http.StatusTooManyRequests
+	case CodeLLMTimeout:
+		return http.StatusGatewayTimeout
+	case CodeLLMUpstream, CodeStoragePutFailed, CodeStorageGetFailed:
+		return http.StatusBadGateway
+	case CodeLLMContextTooLong:
+		return http.StatusBadRequest
 	default:
 		return http.StatusInternalServerError
 	}