feat(misc): hold the wheel spin with a placeholder message

A remote wheel render takes several seconds, during which /wheelofnames
looked unresponsive. Post "Spinning..." first, then let the result take
its place: the GIF replaces it (send-then-delete, since Telegram cannot
edit text into media) and any render or upload failure edits the same
message into the plain text winner. A rejected edit still falls back to a
fresh reply so the chat never stays stuck on "Spinning...".

No placeholder when no renderer is configured — the winner reply is
already immediate there and would only flash.

Adds SendText/EditText/DeleteMessage to chathelper; Reply now delegates
to SendText.

docs/deploy-coolify-selfhosted.md

@@ -72,6 +72,12 @@ service is unset, unavailable, unauthorized, or returns a non-GIF response,
 `/wheelofnames` falls back to the same plain text winner reply as `/random`.
 Successful GIF replies include the result behind Telegram spoiler formatting.
 
+When a renderer is configured, the bot posts a `Spinning...` holding message
+first, because the render takes several seconds. The GIF then replaces it; a
+render or upload failure edits that same message into the plain text winner
+instead. With no renderer configured there is no holding message — the winner
+reply is immediate.
+
 ## 1. MongoDB Atlas (M0)
 
 1. Create a free **M0** cluster (512 MB — ample for the tiny paper-trading KV).