refactor(repo): replace legacy openflare-server with Wavelet rename

Delete the old monolithic openflare-server implementation and rename
Wavelet/ to openflare-server/ to complete the migration consolidation.
Update CI workflows, agent Dockerfiles, and deployment docs for the new
layout (frontend/, docker/Dockerfile).

openflare-server/internal/util/errs.go

@@ -0,0 +1,10 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package util
+
+const (
+	errCreateHTTPRequestFailed = "创建HTTP请求失败: %w"
+	errHTTPRequestFailed       = "请求%s接口失败: %w"
+	errInvalidCustomValue      = "invalid value: %v"
+)