refactor: 将客服后端重构为宿主可嵌入模块

- 注入数据库、运行时配置、统一响应、文件存储和平台 AI 能力，补充业务读写工具与客户快捷操作契约。

- 移除模块内重复的组织、客户、工单、标签、技能、旧工作流、MCP 和迁移实现，将身份权限与业务主体交由宿主管理。

- 使用 libSQL 重构向量存储，并完善图片消息、访客身份、排队调度、企业微信和支持聊天页面。

- 统一 HTTP、DTO 与 WebSocket 的 snake_case 协议，补齐模块初始化、业务动作和公共载荷等回归测试。

internal/web/supportchat/handler.go

@@ -0,0 +1,52 @@
+package supportchat
+
+import (
+	"embed"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+// assets contains the self-contained customer chat page served by the Agent Desk backend.
+//
+//go:embed assets/*
+var assets embed.FS
+
+// RegisterRoutes registers the H5 support chat page and its static assets.
+func RegisterRoutes(router gin.IRouter) {
+	router.GET("/support/chat", serveIndex)
+	router.GET("/support/chat/", serveIndex)
+	router.GET("/support/chat/chat.css", serveAsset("assets/chat.css", "text/css; charset=utf-8"))
+	router.GET("/support/chat/chat.js", serveAsset("assets/chat.js", "application/javascript; charset=utf-8"))
+	router.GET("/support/demo", serveDemo)
+	router.GET("/support/demo/", serveDemo)
+	router.GET("/support/demo/demo.css", serveAsset("assets/demo.css", "text/css; charset=utf-8"))
+	router.GET("/support/demo/demo.js", serveAsset("assets/demo.js", "application/javascript; charset=utf-8"))
+	// Keep assets working when /support/demo is opened without the trailing slash.
+	router.GET("/support/demo.css", serveAsset("assets/demo.css", "text/css; charset=utf-8"))
+	router.GET("/support/demo.js", serveAsset("assets/demo.js", "application/javascript; charset=utf-8"))
+}
+
+func serveIndex(ctx *gin.Context) {
+	serveEmbeddedFile(ctx, "assets/index.html", "text/html; charset=utf-8")
+}
+
+func serveDemo(ctx *gin.Context) {
+	serveEmbeddedFile(ctx, "assets/demo.html", "text/html; charset=utf-8")
+}
+
+func serveAsset(name string, contentType string) gin.HandlerFunc {
+	return func(ctx *gin.Context) {
+		serveEmbeddedFile(ctx, name, contentType)
+	}
+}
+
+func serveEmbeddedFile(ctx *gin.Context, name string, contentType string) {
+	data, err := assets.ReadFile(name)
+	if err != nil {
+		ctx.AbortWithStatus(http.StatusNotFound)
+		return
+	}
+	ctx.Header("Cache-Control", "no-cache")
+	ctx.Data(http.StatusOK, contentType, data)
+}