feat(update): add rolling dev update channel for per-commit builds

Adds an opt-in Dev channel so panels running CI per-commit builds can self-update to the latest commit, mirroring the stable online-update flow.

CI publishes/overwrites a single fixed-tag pre-release (dev-latest), force-moved to the newest main commit and marked --latest=false so releases/latest stays the stable tag. Builds stamp the short commit via -ldflags; the panel compares the running commit to the dev release commit to detect an update, and update.sh honors XUI_UPDATE_TAG to install from that tag. Linux/systemd only.

internal/web/controller/server.go

@@ -69,6 +69,7 @@ func (a *ServerController) initRouter(g *gin.RouterGroup) {
 	g.POST("/restartXrayService", a.restartXrayService)
 	g.POST("/installXray/:version", a.installXray)
 	g.POST("/updatePanel", a.updatePanel)
+	g.POST("/setUpdateChannel", a.setUpdateChannel)
 	g.POST("/updateGeofile", a.updateGeofile)
 	g.POST("/updateGeofile/:fileName", a.updateGeofile)
 	g.POST("/logs/:count", a.getLogs)
@@ -211,6 +212,19 @@ func (a *ServerController) updatePanel(c *gin.Context) {
 	jsonMsg(c, I18nWeb(c, "pages.index.panelUpdateStartedPopover"), err)
 }
 
+// setUpdateChannel toggles whether self-update tracks the rolling dev release.
+func (a *ServerController) setUpdateChannel(c *gin.Context) {
+	var req struct {
+		Dev bool `json:"dev"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		jsonMsg(c, "invalid data", err)
+		return
+	}
+	err := a.settingService.SetDevChannelEnable(req.Dev)
+	jsonMsg(c, I18nWeb(c, "pages.index.updateChannelChanged"), err)
+}
+
 // updateGeofile updates the specified geo file for Xray.
 func (a *ServerController) updateGeofile(c *gin.Context) {
 	fileName := c.Param("fileName")