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/config/routers.go

@@ -0,0 +1,57 @@
+// Copyright 2025 linux.do
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package config 提供公开配置查询接口
+package config
+
+import (
+	"net/http"
+
+	"github.com/Rain-kl/Wavelet/internal/model"
+	"github.com/Rain-kl/Wavelet/internal/repository"
+	"github.com/gin-gonic/gin"
+
+	"github.com/Rain-kl/Wavelet/internal/common/response"
+)
+
+// GetPublicConfig 获取公共配置
+// @Summary 获取公共配置
+// @Description 返回系统配置表中 visibility 为 1 的配置键值集合
+// @Tags config
+// @Accept json
+// @Produce json
+// @Success 200 {object} response.Any
+// @Router /api/v1/config/public [get]
+func GetPublicConfig(c *gin.Context) {
+	ctx := c.Request.Context()
+	configs, err := repository.ListVisibleSystemConfigs(ctx)
+	if err != nil {
+		response.AbortInternal(c, err.Error())
+		return
+	}
+
+	resp := make(map[string]string, len(configs))
+	for _, config := range configs {
+		resp[config.Key] = config.Value
+	}
+
+	c.JSON(http.StatusOK, response.OK(resp))
+}
+
+// GetRobotsTXT 动态生成 robots.txt
+// @Summary 获取 robots.txt
+// @Description 根据系统配置决定是否允许搜索引擎检索，并返回相应的 robots.txt 文件内容
+// @Tags config
+// @Produce text/plain
+// @Success 200 {string} string "robots.txt 内容"
+// @Router /robots.txt [get]
+func GetRobotsTXT(c *gin.Context) {
+	ctx := c.Request.Context()
+	enabled, err := repository.GetBoolByKey(ctx, model.ConfigKeySearchEngineIndexingEnabled)
+	content := "User-Agent: *\nDisallow: /\n"
+	if err == nil && enabled {
+		content = "User-Agent: *\nAllow: /\n"
+	}
+	c.Data(http.StatusOK, "text/plain; charset=utf-8", []byte(content))
+}