Refactor API routes and controllers for improved structure and clarity

- Updated API route structure to remove versioning and consolidate endpoints.
- Refactored routing in `server.go` to use a unified `/api` prefix for all controllers.
- Added new `ChannelController`, `ConversationController`, and `MessageController` to handle specific API functionalities.
- Removed deprecated `OpenImContextMiddleware` and related logic.
- Enhanced channel validation logic in `ChannelService` and `ChannelRepository`.
- Updated frontend API calls to align with new endpoint structure.

internal/middleware/open_im_middleware.go

@@ -3,38 +3,13 @@ package middleware
 import (
 	"cs-agent/internal/pkg/irisx"
 	"cs-agent/internal/pkg/openidentity"
-	"cs-agent/internal/services"
-	"strings"
 
 	"github.com/kataras/iris/v12"
 	"github.com/mlogclub/simple/web"
 )
 
-// OpenImContextMiddleware 校验 X-Channel-Id / channelId 对应启用 web 渠道；除 /api/open/im/widget 外解析并缓存外部访客身份。
-func OpenImContextMiddleware(ctx iris.Context) {
-	channelID := strings.TrimSpace(ctx.GetHeader("X-Channel-Id"))
-	if channelID == "" {
-		channelID = strings.TrimSpace(ctx.URLParam("channelId"))
-	}
-	if channelID == "" {
-		ctx.StopExecution()
-		_ = ctx.JSON(web.JsonErrorMsg("channelId不能为空"))
-		return
-	}
-	channel := services.ChannelService.GetEnabledWebChannelByChannelID(channelID)
-	if channel == nil {
-		ctx.StopExecution()
-		_ = ctx.JSON(web.JsonErrorMsg("接入渠道不存在或已停用"))
-		return
-	}
-	irisx.SetOpenImChannel(ctx, channel)
-
-	path := ctx.Path()
-	if strings.Contains(path, "/open/im/widget") {
-		ctx.Next()
-		return
-	}
-
+// ChannelContextMiddleware 校验 X-Channel-Id / channelId 对应启用 web 渠道
+func ChannelContextMiddleware(ctx iris.Context) {
 	ext, err := openidentity.GetExternalInfo(ctx)
 	if err != nil {
 		ctx.StopExecution()