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/adminconsole/views.go

@@ -195,6 +195,52 @@ type UserDetailView struct {
 	Blocks    []RelationRow
 	BlockedBy []RelationRow
 	Friends   []RelationRow
+	// Finance is the account's payments picture (balances, benefits, refund risk, ledger). Present
+	// is false when the payments domain is unwired.
+	Finance FinanceView
+}
+
+// FinanceView is the account's payments picture on the user card: chip balances per funding
+// segment, benefits per origin, the recorded refund risk, and the append-only ledger history
+// (newest first). Present is false when the payments domain is unwired.
+type FinanceView struct {
+	Present  bool
+	Segments []SegmentRow
+	Benefits []BenefitRow
+	// Abuse is the refund abuse flag; Loss is the unrecoverable chip loss from floor-0 refunds.
+	Abuse  bool
+	Loss   int
+	Ledger []LedgerRow
+}
+
+// SegmentRow is one funding segment's chip balance.
+type SegmentRow struct {
+	Source string
+	Chips  int
+}
+
+// BenefitRow is one origin's benefit: the hint wallet, the ad-free expiry (pre-formatted, empty
+// when none) and the lifetime ad-free flag.
+type BenefitRow struct {
+	Origin   string
+	Hints    int
+	AdsUntil string
+	Forever  bool
+}
+
+// LedgerRow is one append-only ledger entry: its kind, funding source / benefit origin, signed chip
+// delta, the product / order / provider it references (empty when none), the raw snapshot JSON and
+// the pre-formatted time.
+type LedgerRow struct {
+	Kind       string
+	Source     string
+	Origin     string
+	ChipsDelta int
+	Product    string
+	Order      string
+	Provider   string
+	Snapshot   string
+	At         string
 }
 
 // RelationRow is one cross-linked account in the user card's blocks / blocked-by / friends