Coop: surface per-gift countdowns in !coop status

Each gift now has its own 6h voting window, but the only places the
remaining time was visible were the original arrival post and any
edit-triggered re-render after a vote. Mid-window the displayed
countdown was stale.

!coop status now lists pending gifts (anything with vote_result still
NULL on this run) with current open/leave tally and a fresh per-gift
countdown derived from expires_at. The party can poll this any time to
see what's about to close.

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

internal/plugin/coop_dungeon_render.go

@@ -216,5 +216,42 @@ func renderCoopStatus(p *AdventurePlugin, run *CoopRun, members []CoopMember) st
 		sb.WriteString("\n")
 		sb.WriteString(renderCoopOddsLine(run, members, bets))
 	}
+
+	// Pending gift list with per-gift countdowns. Voting windows expire
+	// independently throughout the day, so this is the canonical place to
+	// see what's still open.
+	if run.Status == "active" {
+		all, _ := loadAllCoopGifts(run.ID)
+		var pending []CoopGift
+		for _, g := range all {
+			if g.VoteResult == "" {
+				pending = append(pending, g)
+			}
+		}
+		if len(pending) > 0 {
+			sb.WriteString("\n\nPending gifts:\n")
+			for _, g := range pending {
+				opens, leaves := 0, 0
+				for _, v := range g.Votes {
+					if v == "open" {
+						opens++
+					} else if v == "leave" {
+						leaves++
+					}
+				}
+				countdown := "—"
+				if g.ExpiresAt != nil {
+					remaining := time.Until(*g.ExpiresAt).Truncate(time.Minute)
+					if remaining > 0 {
+						countdown = remaining.String()
+					} else {
+						countdown = "closing"
+					}
+				}
+				sb.WriteString(fmt.Sprintf("  #%d (day %d) — open %d / leave %d — closes in %s\n",
+					g.ID, g.Day, opens, leaves, countdown))
+			}
+		}
+	}
 	return sb.String()
 }