fix(discord): address review on #741

Builds the alert tail only for a post that goes out; separates deduped from disabled and never dedupes a deliberate notify; types the startup hint with fromUser false and skips resumed, remote and Docker tabs; clears per-tab maps and closes the bridge on stop; acts only on a real delete, not a detach; serialises thread-map writes; reloads the bridge after a discord.json restore; probes and self-ignores .codeman-discord; validates the message id; reacts when a reply is rate limited; documents what leaves the machine.

docs/wiki/Discord-Bridge.md

@@ -55,7 +55,7 @@ An agent only posts deliberately if it knows it can. With **Tell each CLI how to
 
 - **Claude** is launched with the instruction as part of its system prompt, so nothing shows in the chat.
 - **Every other CLI** is sent the same text once, as a message, the first time a brand-new tab goes idle.
-  Restored tabs, resumed tabs and shell tabs are never sent it.
+  Restored tabs, resumed tabs, shell tabs, and remote (ssh) and Docker tabs (which have no `codeman` command) are never sent it.
 
 Tabs that were already open when you turned the bridge on are not told. The alerts still reach
 Discord for them; only the agent-initiated `codeman notify` habit is missing.