feat(admin): per-user finance panel — balances, benefits, risk, ledger

The /_gm user card gains a Finance panel: an account's chip balances per
funding segment, benefits per origin (hints, no-ads until/forever), the
recorded refund risk (abuse flag + floor-0 loss), and the append-only ledger
history newest-first. Backed by a new payments.AccountStatement read straight
from the materialized tables + the ledger (uncached — an admin, rare view).

Folds the agreed admin / reports / catalog plan into PLAN.md (the PR stack:
this panel, then the catalog editor, admin grant, refund + ledger export) and
moves the tournament-entry storage design to the tournament stage.

backend/internal/server/handlers_admin_console.go

@@ -21,6 +21,7 @@ import (
 	"scrabble/backend/internal/dictadmin"
 	"scrabble/backend/internal/engine"
 	"scrabble/backend/internal/game"
+	"scrabble/backend/internal/payments"
 	"scrabble/backend/internal/ratewatch"
 	"scrabble/backend/internal/robot"
 	"scrabble/backend/internal/social"
@@ -436,9 +437,40 @@ func (s *Server) consoleUserDetail(c *gin.Context) {
 			view.Friends = relationRows(rels)
 		}
 	}
+	if s.payments != nil {
+		if stmt, err := s.payments.AccountStatement(ctx, id); err == nil {
+			view.Finance = financeView(stmt)
+		} else {
+			s.log.Warn("console: account statement failed", zap.String("account", id.String()), zap.Error(err))
+		}
+	}
 	s.renderConsole(c, "user_detail", "users", acc.DisplayName, view)
 }
 
+// financeView projects an account's payments statement into the user-card finance panel, with the
+// benefit expiry and ledger times pre-formatted for the logic-free template.
+func financeView(stmt payments.Statement) adminconsole.FinanceView {
+	fv := adminconsole.FinanceView{Present: true, Abuse: stmt.Risk.Abuse, Loss: stmt.Risk.LossChips}
+	for _, sg := range stmt.Segments {
+		fv.Segments = append(fv.Segments, adminconsole.SegmentRow{Source: string(sg.Source), Chips: sg.Chips})
+	}
+	for _, b := range stmt.Benefits {
+		row := adminconsole.BenefitRow{Origin: string(b.Origin), Hints: b.Hints, Forever: b.AdsForever}
+		if !b.AdsPaidUntil.IsZero() {
+			row.AdsUntil = fmtTime(b.AdsPaidUntil)
+		}
+		fv.Benefits = append(fv.Benefits, row)
+	}
+	for _, e := range stmt.Ledger {
+		fv.Ledger = append(fv.Ledger, adminconsole.LedgerRow{
+			Kind: e.Kind, Source: e.Source, Origin: e.Origin, ChipsDelta: e.ChipsDelta,
+			Product: e.ProductID, Order: e.OrderID, Provider: e.Provider, Snapshot: e.Snapshot,
+			At: fmtTime(e.CreatedAt),
+		})
+	}
+	return fv
+}
+
 // relationRows maps the social graph entries to the cross-linked, date-formatted rows the
 // user card renders.
 func relationRows(rels []social.AdminRelation) []adminconsole.RelationRow {