fix: register forum/thread routes at top level + notification dots in ServerBar

Moved thread and forum-tag routes from nested /servers/{sid}/channels/ to
top-level /channels/{id}/... to match frontend API calls. Forum posts were
getting SPA HTML fallback instead of JSON.

Added orange notification dots to DM and server buttons in ServerBar.

internal/channel/handlers.go

@@ -27,10 +27,7 @@ func (h *Handler) RegisterRoutes(r chi.Router) {
 	r.Get("/{channelID}", h.Get)
 	r.Patch("/{channelID}", h.Update)
 	r.Delete("/{channelID}", h.Delete)
-	r.Post("/{channelID}/threads", h.CreateThread)
-	r.Get("/{channelID}/threads", h.ListThreads)
-	r.Patch("/threads/{threadID}", h.UpdateThread)
-	h.registerForumRoutes(r)
+	// ponytail: thread + forum routes registered at top level in main.go to match frontend paths
 	h.RegisterCalendarRoutes(r)
 	h.registerDocRoutes(r)
 	h.registerListRoutes(r)