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/adventure_mortgage.go

@@ -0,0 +1,158 @@
+package plugin
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"os"
+	"strconv"
+	"time"
+
+	"gogobee/internal/db"
+)
+
+// ── FRED API Integration ───────────────────────────────────────────────────
+//
+// Pulls the 5/1 ARM rate weekly from FRED (series: MORTGAGE5US).
+// Requires FRED_API_KEY environment variable.
+// Falls back to a hardcoded default if the API is unavailable.
+
+const fredSeries = "MORTGAGE5US"
+const defaultMortgageRate = 6.5
+const currentRateCacheKey = "mortgage_current_rate"
+
+type fredResponse struct {
+	Observations []struct {
+		Date  string `json:"date"`
+		Value string `json:"value"`
+	} `json:"observations"`
+}
+
+// fetchFREDRate pulls the latest 5/1 ARM rate from the FRED API.
+func fetchFREDRate() (float64, error) {
+	apiKey := os.Getenv("FRED_API_KEY")
+	if apiKey == "" {
+		return 0, fmt.Errorf("FRED_API_KEY not set")
+	}
+
+	url := fmt.Sprintf(
+		"https://api.stlouisfed.org/fred/series/observations?series_id=%s&api_key=%s&file_type=json&sort_order=desc&limit=1",
+		fredSeries, apiKey,
+	)
+
+	client := &http.Client{Timeout: 10 * time.Second}
+	resp, err := client.Get(url)
+	if err != nil {
+		return 0, fmt.Errorf("FRED API request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 {
+		return 0, fmt.Errorf("FRED API status %d", resp.StatusCode)
+	}
+
+	var data fredResponse
+	if err := json.NewDecoder(resp.Body).Decode(&data); err != nil {
+		return 0, fmt.Errorf("FRED JSON decode: %w", err)
+	}
+
+	if len(data.Observations) == 0 {
+		return 0, fmt.Errorf("FRED: no observations returned")
+	}
+
+	val := data.Observations[0].Value
+	if val == "." {
+		return 0, fmt.Errorf("FRED: value is placeholder")
+	}
+
+	rate, err := strconv.ParseFloat(val, 64)
+	if err != nil {
+		return 0, fmt.Errorf("FRED: parse rate %q: %w", val, err)
+	}
+
+	// Clamp to sane range
+	if rate < 1.0 {
+		rate = 1.0
+	}
+	if rate > 15.0 {
+		rate = 15.0
+	}
+
+	return rate, nil
+}
+
+// getCurrentMortgageRate returns the cached rate, or fetches fresh if stale (daily).
+func getCurrentMortgageRate() float64 {
+	// Check DB cache (24h TTL)
+	if val := db.CacheGet(currentRateCacheKey, 24*3600); val != "" {
+		if rate, err := strconv.ParseFloat(val, 64); err == nil {
+			return rate
+		}
+	}
+
+	rate, err := fetchFREDRate()
+	if err != nil {
+		slog.Warn("mortgage: FRED fetch failed, using default", "err", err)
+		return defaultMortgageRate
+	}
+
+	db.CacheSet(currentRateCacheKey, strconv.FormatFloat(rate, 'f', 2, 64))
+	return rate
+}
+
+// ── Weekly Mortgage Ticker ─────────────────────────────────────────────────
+
+func (p *AdventurePlugin) mortgageTicker() {
+	ticker := time.NewTicker(1 * time.Hour)
+	defer ticker.Stop()
+
+	for range ticker.C {
+		now := time.Now().UTC()
+		// Run on Mondays only (FRED updates Thursdays, we process Mondays)
+		if now.Weekday() != time.Monday {
+			continue
+		}
+
+		_, week := now.ISOWeek()
+		dateKey := fmt.Sprintf("%d-W%02d", now.Year(), week)
+		jobName := "mortgage_weekly"
+		if db.JobCompleted(jobName, dateKey) {
+			continue
+		}
+
+		slog.Info("mortgage: running weekly payment processing")
+
+		// Fetch fresh rate and compare with previous
+		newRate := getCurrentMortgageRate()
+		oldRate := p.getLastKnownRate()
+
+		if oldRate > 0 && oldRate != newRate {
+			p.sendMortgageRateChangeDMs(oldRate, newRate)
+		}
+		p.setLastKnownRate(newRate)
+
+		// Process payments
+		p.processMortgagePayments()
+
+		db.MarkJobCompleted(jobName, dateKey)
+	}
+}
+
+const lastKnownRateCacheKey = "mortgage_last_known_rate"
+
+func (p *AdventurePlugin) getLastKnownRate() float64 {
+	val := db.CacheGet(lastKnownRateCacheKey, 365*24*3600) // 1 year TTL
+	if val == "" {
+		return 0
+	}
+	rate, err := strconv.ParseFloat(val, 64)
+	if err != nil {
+		return 0
+	}
+	return rate
+}
+
+func (p *AdventurePlugin) setLastKnownRate(rate float64) {
+	db.CacheSet(lastKnownRateCacheKey, strconv.FormatFloat(rate, 'f', 2, 64))
+}