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/mock/client.ts

@@ -13,6 +13,7 @@ import type {
 import { GatewayError } from '../client';
 import type {
   AccountRef,
+  BlockStatus,
   ChatMessage,
   EvalResult,
   FriendCode,
@@ -139,6 +140,10 @@ export class MockGateway implements GatewayClient {
   async profileGet(): Promise<Profile> {
     return { ...this.profile };
   }
+  async blockStatus(): Promise<BlockStatus> {
+    // The mock never blocks; the blocked screen is driven directly via the mock-mode __block seam.
+    return { blocked: false, permanent: false, until: '', reason: '' };
+  }
   async gamesList(): Promise<GameList> {
     return { games: [...this.games.values()].map((g) => structuredClone(g.view)) };
   }