Show product usage types in credit ledger

Persist hotword request origin so every reservation lifecycle entry can be classified without mutating the immutable ledger.

admin-web/src/api/types.ts

@@ -98,6 +98,8 @@ export type LedgerEntryType =
   | "refund"
   | "adjustment";
 
+export type UsageType = "polish" | "asr" | "ai" | "agent" | "hotword";
+
 export interface LedgerEntry {
   entryId: string;
   userId: string;
@@ -105,6 +107,7 @@ export interface LedgerEntry {
   amount: number;
   balanceAfter: number;
   reasonCode: string;
+  usageType?: UsageType;
   createdAt: string;
 }