Stage 8: UI social/account/history surfaces

Wire the deferred Stage 7 surfaces end-to-end (UI -> gateway transcode ->
backend REST -> existing domain services): friends (incl. one-time friend
codes), per-user blocks, friend-game invitations, profile editing + email
binding, the statistics screen, and the in-game history + GCG export.

Friends gain two add paths (interview decision, a deliberate plan change):
one-time 6-digit codes (friend_codes table, 12h TTL, single-use, rate-limited
redeem); and play-gated requests (shared game required) where an explicit
decline is permanent, an ignored request lapses after 30 days, and a code
bypasses a decline. Migration 00006 widens friendships_status_chk and adds
friend_codes.

Lobby notification badge is poll + push: a new generic `notify` event drives
it live; the client polls on open/focus. Language stays a single Settings
control that writes through to the durable account's preferred_language. GCG
export is finished-only (game.ErrGameActive) and shares/downloads the .gcg file.

Tests: backend unit + inttest (friend gate/decline/code, ListInvitations,
GetStats, GCG gate), gateway transcode round-trips + notify constructor, UI
vitest (codecs, win-rate, share choice) + Playwright social specs. Docs: PLAN
(Stage 8 done + refinements + TODO-5), ARCHITECTURE, FUNCTIONAL(+ru), UI_DESIGN,
TESTING, module READMEs.

ui/src/lib/transport.ts

@@ -119,6 +119,73 @@ export function createTransport(baseUrl: string): GatewayClient {
       return codec.decodeChatMessage(await exec('chat.nudge', codec.encodeGameAction(id)));
     },
 
+    async friendsList() {
+      return codec.decodeFriendList(await exec('friends.list', codec.empty()));
+    },
+    async friendsIncoming() {
+      return codec.decodeIncomingList(await exec('friends.incoming', codec.empty()));
+    },
+    async friendRequest(accountId) {
+      await exec('friends.request', codec.encodeTarget(accountId));
+    },
+    async friendRespond(requesterId, accept) {
+      await exec('friends.respond', codec.encodeFriendRespond(requesterId, accept));
+    },
+    async friendCancel(accountId) {
+      await exec('friends.cancel', codec.encodeTarget(accountId));
+    },
+    async unfriend(accountId) {
+      await exec('friends.unfriend', codec.encodeTarget(accountId));
+    },
+    async friendCodeIssue() {
+      return codec.decodeFriendCode(await exec('friends.code.issue', codec.empty()));
+    },
+    async friendCodeRedeem(code) {
+      return codec.decodeRedeemResult(await exec('friends.code.redeem', codec.encodeRedeemCode(code)));
+    },
+
+    async blocksList() {
+      return codec.decodeBlockList(await exec('blocks.list', codec.empty()));
+    },
+    async block(accountId) {
+      await exec('blocks.add', codec.encodeTarget(accountId));
+    },
+    async unblock(accountId) {
+      await exec('blocks.remove', codec.encodeTarget(accountId));
+    },
+
+    async invitationsList() {
+      return codec.decodeInvitationList(await exec('invitation.list', codec.empty()));
+    },
+    async invitationCreate(inviteeIds, settings) {
+      return codec.decodeInvitation(await exec('invitation.create', codec.encodeCreateInvitation(inviteeIds, settings)));
+    },
+    async invitationAccept(invitationId) {
+      return codec.decodeInvitation(await exec('invitation.accept', codec.encodeInvitationAction(invitationId)));
+    },
+    async invitationDecline(invitationId) {
+      return codec.decodeInvitation(await exec('invitation.decline', codec.encodeInvitationAction(invitationId)));
+    },
+    async invitationCancel(invitationId) {
+      await exec('invitation.cancel', codec.encodeInvitationAction(invitationId));
+    },
+
+    async profileUpdate(p) {
+      return codec.decodeProfile(await exec('profile.update', codec.encodeUpdateProfile(p)));
+    },
+    async emailBindRequest(email) {
+      await exec('email.bind.request', codec.encodeEmailBind(email));
+    },
+    async emailBindConfirm(email, code) {
+      return codec.decodeProfile(await exec('email.bind.confirm', codec.encodeEmailConfirm(email, code)));
+    },
+    async statsGet() {
+      return codec.decodeStats(await exec('stats.get', codec.empty()));
+    },
+    async exportGcg(gameId) {
+      return codec.decodeGcg(await exec('game.gcg', codec.encodeGameAction(gameId)));
+    },
+
     subscribe(onEvent, onError) {
       const ctrl = new AbortController();
       void (async () => {