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/version/version.go

@@ -0,0 +1,28 @@
+package version
+
+import (
+	"fmt"
+	"runtime"
+)
+
+const Version = "1.0.0"
+
+var (
+	Commit    = "dev"
+	BuildDate = "unknown"
+)
+
+func Full() string {
+	return fmt.Sprintf("GogoBee v%s (%s, %s, %s)", Version, Commit, BuildDate, runtime.Version())
+}
+
+func Short() string {
+	return fmt.Sprintf("v%s-%s", Version, shortCommit())
+}
+
+func shortCommit() string {
+	if len(Commit) > 7 {
+		return Commit[:7]
+	}
+	return Commit
+}