Add anti-raid and anti-nuke protection

Join Gate (account age, avatar, advertising and username filters, bot
checks), raid detection with invite pausing, anti-nuke quarantine of
admins who mass delete, manual and automatic lockdowns, a decaying heat
score against spam, role and channel snapshots with restore, and alert
DMs to the owner and trusted users. Everything that weakens protection
is limited to the owner and the trusted list.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

internal/commands/help/help.go

@@ -93,6 +93,16 @@ func HelpHandler(s *discordgo.Session, i *discordgo.InteractionCreate) {
 					"`/ticket claim`, `/ticket remove user:@someone` — Staff only\n" +
 					"`/tickets setup`, `/tickets category add|remove|list`, `/tickets panel` — Set up (**Manage Server**)",
 			},
+			{
+				Name: "Security (anti-raid & anti-nuke)",
+				Value: "" +
+					"`/security status` — What's on and who is trusted\n" +
+					"`/security toggle` — Join Gate, raid mode, anti-nuke on/off (off: owner or trusted)\n" +
+					"`/security alerts`, `/security quarantine-role`, `/security release`, `/security end-raid` — Owner or trusted\n" +
+					"`/security trust add|remove` — Owner only\n" +
+					"`/security snapshot` — Save roles and channels; `/security restore` — Rebuild what a nuke deleted (owner or trusted)\n" +
+					"`/lockdown channel|server|joins`, `/unlock …` (unlock: owner or trusted)",
+			},
 			{
 				Name: "Meetings (**Manage Server**)",
 				Value: "" +