refactor(repo): consolidate openflare-server to root and move subprojects to internal/apps

- Merge all files inside openflare-server to the repository root directory.
- Relocate agent, relay, and flared subprojects from internal/ to internal/apps/.
- Combine docker-compose files and update build context paths to root.
- Update GitHub workflows and Dockerfiles to refer to new directories and package names.
- Rewrite Go package imports across all files.
- Resolve database renew test race condition and clean up docs.

internal/apps/health/routers.go

@@ -0,0 +1,25 @@
+// Copyright 2025 linux.do
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package health 提供健康检查端点
+package health
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/Rain-kl/Wavelet/internal/common/response"
+)
+
+// Health 健康检查
+// @Summary 健康检查
+// @Description 检查服务是否正常运行，可用于负载均衡存活探测
+// @Tags health
+// @Produce json
+// @Success 200 {object} response.Any{data=string} "服务正常"
+// @Router /api/health [get]
+func Health(c *gin.Context) {
+	c.JSON(http.StatusOK, response.OKNil())
+}