feat(admin): manual account blocking (suspensions)

Operator-driven hard block, the counterpart to the soft high-rate flag: permanent or until a date, with an optional reason chosen from an editable en+ru picklist (snapshotted onto the block). A block forfeits the player's active games (opponent wins, as a resignation) and cancels their open matchmaking games. A backend gate refuses a blocked account on every /api/v1/user/* route except the block-status probe with 403 account_blocked, which threads through the gateway as the Execute result_code; the UI surfaces it as a terminal blocked screen and stops all push/poll. Temporary blocks self-expire; the operator can unblock at any time (lost games stay lost). Sessions are not revoked, so the blocked client can still reach the exempt block-status endpoint.

Backend: migration 00003 (account_suspensions + suspension_reasons) + jet regen; account suspension store; game.ForfeitAllForAccount; requireNotSuspended gate + block-status endpoint; admin console block/unblock + Reasons CRUD. Wire: fbs BlockStatus + account.block_status gateway op. UI: blocked screen, app state, transport/codec, i18n. Docs: ARCHITECTURE, FUNCTIONAL(+ru), PRERELEASE (AB).

ui/src/lib/model.ts

@@ -121,6 +121,18 @@ export interface Profile {
   notificationsInAppOnly: boolean;
 }
 
+/** BlockStatus is the caller's current manual block, fetched after any call reports
+ *  the "account_blocked" code. When blocked the app shows the terminal blocked screen
+ *  and stops all push/poll. */
+export interface BlockStatus {
+  blocked: boolean;
+  permanent: boolean;
+  /** RFC3339 UTC instant for a temporary block; "" for a permanent one or when not blocked. */
+  until: string;
+  /** Operator reason resolved to the account's language; "" when none was cited. */
+  reason: string;
+}
+
 /** The full editable profile sent to profileUpdate (overwrites every field). */
 export interface ProfileUpdate {
   displayName: string;