Adv 2.0 D&D Phase 12 E2e: !threat command

§14 surfaces the threat clock as a first-class command. !threat shows
level/100, current band, the per-band combat & supply effects (built
from ThreatBandInfo so display tracks any future band re-tuning), and
the last 5 ThreatEvent log entries with deltas + reasons. Adds a
"siege is active" / "past 70" footer when those gates have triggered.

Active-enemy camp guard and close-call evening recap stay deferred —
both need combat state inside an expedition, which doesn't exist yet
(expeditions still don't host their own combat loop). They land in the
combat-link phase along with the §8.1 combat-driven threat modifiers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/plugin/adventure.go

@@ -258,6 +258,9 @@ func (p *AdventurePlugin) OnMessage(ctx MessageContext) error {
 	if p.IsCommand(ctx.Body, "camp") {
 		return p.handleCampCmd(ctx, p.GetArgs(ctx.Body, "camp"))
 	}
+	if p.IsCommand(ctx.Body, "threat") {
+		return p.handleThreatCmd(ctx)
+	}
 
 	// 1. Arena commands (work in rooms and DMs)
 	if p.IsCommand(ctx.Body, "bail") {