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).

gateway/internal/transcode/transcode.go

@@ -22,6 +22,7 @@ const (
 	MsgAuthEmailReq   = "auth.email.request"
 	MsgAuthEmailLogin = "auth.email.login"
 	MsgProfileGet     = "profile.get"
+	MsgBlockStatus    = "account.block_status"
 	MsgGameSubmitPlay = "game.submit_play"
 	MsgGameState      = "game.state"
 	MsgLobbyEnqueue   = "lobby.enqueue"
@@ -95,6 +96,7 @@ func NewRegistry(backend *backendclient.Client, tg TelegramValidator, defaultLan
 	r.ops[MsgAuthEmailReq] = Op{Handler: authEmailRequestHandler(backend), Email: true}
 	r.ops[MsgAuthEmailLogin] = Op{Handler: authEmailLoginHandler(backend, defaultLanguages), Email: true}
 	r.ops[MsgProfileGet] = Op{Handler: profileHandler(backend), Auth: true}
+	r.ops[MsgBlockStatus] = Op{Handler: blockStatusHandler(backend), Auth: true}
 	r.ops[MsgGameSubmitPlay] = Op{Handler: submitPlayHandler(backend), Auth: true}
 	r.ops[MsgGameState] = Op{Handler: gameStateHandler(backend), Auth: true}
 	r.ops[MsgLobbyEnqueue] = Op{Handler: enqueueHandler(backend), Auth: true}
@@ -199,6 +201,16 @@ func profileHandler(backend *backendclient.Client) Handler {
 	}
 }
 
+func blockStatusHandler(backend *backendclient.Client) Handler {
+	return func(ctx context.Context, req Request) ([]byte, error) {
+		bs, err := backend.BlockStatus(ctx, req.UserID)
+		if err != nil {
+			return nil, err
+		}
+		return encodeBlockStatus(bs), nil
+	}
+}
+
 func submitPlayHandler(backend *backendclient.Client) Handler {
 	return func(ctx context.Context, req Request) ([]byte, error) {
 		in := fb.GetRootAsSubmitPlayRequest(req.Payload, 0)