Add version system, tax tracking, lottery winner DMs, fmtEuro, audit fixes

- Version system: per-plugin versions via Versioned interface, crash_log and
  version_history DB tables, !version command, crash stats in !botinfo
- Tax tracking: tax_ledger table, trackTaxPaid across all communityTax and
  communityPotAdd sites, tax paid display in !stats and !superstatsexplusalpha
- Lottery: DM winners with winning ticket details and matched numbers bolded
- fmtEuro: generic currency formatter with thousand separators across all
  economy display paths
- Audit fixes: streak_decayed column for Streak Survivor achievement,
  combat_narrative empty-phase guard, crafting success rate integer division,
  RecordCrash nil-DB guard

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

internal/plugin/adventure_events.go

@@ -176,8 +176,9 @@ func (p *AdventurePlugin) handleEventRespond(ctx MessageContext) error {
 		gold += rand.Int64N(event.GoldMax - event.GoldMin + 1)
 	}
 
-	// Credit gold
-	p.euro.Credit(ctx.Sender, float64(gold), "adventure_event_"+event.Key)
+	// Credit gold (5% community tax)
+	net, _ := communityTax(ctx.Sender, float64(gold), 0.05)
+	p.euro.Credit(ctx.Sender, net, "adventure_event_"+event.Key)
 
 	// Apply XP if applicable
 	xpSkill := event.XPSkill