Add housing/pets/Thom Krooke, wordle overhaul, boost system, backup strategy

Part 3 (Housing, Thom Krooke & Pets):
- Housing system with tiered upgrades, mortgage loans, FRED API rates
- Thom Krooke realtor NPC with !thom commands and !thom pay extra principal
- Pet system with arrival, naming, leveling, combat, morning defense
- Pet ditch recovery scales with level, name validation

Wordle overhaul:
- Remove daily expiration — puzzles persist until solved/failed
- Auto-start new puzzle after solve, fail, or skip
- Sequential puzzle IDs instead of date-based
- Auto-create puzzle on first guess if none active

Adventure fixes:
- Double XP/money boost toggle (!adv boost, admin only)
- Fix ensureCharacter wiping existing data on query errors
- Fix rival RPS format string bug
- Fix daily summary empty data (load today+yesterday logs)
- Fix holdem DM-to-room reply routing
- Fix Robbie payout to 25% of item value
- Add fishing to leaderboard and TwinBee calculations
- Add Thom to morning menu
- Persist mortgage rate across restarts via db.CacheGet/Set

Infrastructure:
- Daily database backup via VACUUM INTO with 7-day retention
- Admin DM notification on backup failure (async)
- Daily NPC house balance reset for holdem

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/plugin/plugin.go

@@ -576,10 +576,12 @@ func (b *Base) SendNotice(roomID id.RoomID, text string) error {
 // SendReply sends a reply to a specific event.
 func (b *Base) SendReply(roomID id.RoomID, eventID id.EventID, text string) error {
 	content := textContent(text)
-	content.RelatesTo = &event.RelatesTo{
-		InReplyTo: &event.InReplyTo{
-			EventID: eventID,
-		},
+	if eventID != "" {
+		content.RelatesTo = &event.RelatesTo{
+			InReplyTo: &event.InReplyTo{
+				EventID: eventID,
+			},
+		}
 	}
 	_, err := b.Client.SendMessageEvent(context.Background(), roomID, event.EventMessage, content)
 	if err != nil {