feat(nudge): name the sender; blink lobby cards; re-animate toasts

The "waiting for your move" popup was the nudge (chat.nudge), shown without a
sender name. Resolve the nudger's per-game seat name server-side and carry it on
a new NudgeEvent.sender_name field, so:

- the in-app toast reads "<opponent>: Waiting for your move 🤭" (chat.nudgeBy);
- the out-of-app Telegram push names the sender too (render nudgeBy);

falling back to the plain phrase when the name is absent (RU mirrored). The
your_turn toast already named the opponent and is unchanged.

Lobby: when a card transitions into "your turn" or "finished" while the lobby is
open, its status emoji blinks twice (two 1s fades); the opponent's-turn change
stays in place. Blink state is keyed by game id (SvelteSet + per-id nonce/timer)
so overlapping events animate in isolation; suppressed under reduce-motion.

Toast: a per-message seq re-keys Toast.svelte, so the freshest toast cancels the
previous one and replays its entrance, uniformly on every screen.

Tests: notify.Nudge round-trip + render named/fallback (Go), game.Service.SeatName
(integration), codec/i18n/gamePhase/shouldBlink (UI). Docs (FUNCTIONAL +_ru,
UI_DESIGN) + PLAN TODO-7 (deferred FLIP card-relocation animation) updated.

ui/src/lib/lobbysort.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { groupGames, isMyTurn } from './lobbysort';
+import { gamePhase, groupGames, isMyTurn, shouldBlink } from './lobbysort';
 import type { GameView, Seat } from './model';
 
 const ME = 'me';
@@ -82,3 +82,28 @@ describe('groupGames', () => {
     expect(isMyTurn(game('x', 'open', 0, 0), ME)).toBe(true);
   });
 });
+
+describe('gamePhase', () => {
+  it('maps each game to its lobby bucket (open folds into mine/theirs like active)', () => {
+    expect(gamePhase(game('x', 'active', 0, 0), ME)).toBe('mine');
+    expect(gamePhase(game('x', 'active', 1, 0), ME)).toBe('theirs');
+    expect(gamePhase(game('x', 'open', 0, 0), ME)).toBe('mine');
+    expect(gamePhase(game('x', 'open', 1, 0), ME)).toBe('theirs');
+    expect(gamePhase(game('x', 'finished', 0, 0), ME)).toBe('finished');
+  });
+});
+
+describe('shouldBlink', () => {
+  it('blinks on a transition into mine or finished', () => {
+    expect(shouldBlink('theirs', 'mine')).toBe(true);
+    expect(shouldBlink('mine', 'finished')).toBe(true);
+    expect(shouldBlink('theirs', 'finished')).toBe(true);
+  });
+
+  it('stays quiet on a transition into theirs, a no-op, or a first sighting', () => {
+    expect(shouldBlink('mine', 'theirs')).toBe(false);
+    expect(shouldBlink('mine', 'mine')).toBe(false);
+    expect(shouldBlink(undefined, 'mine')).toBe(false);
+    expect(shouldBlink(undefined, 'finished')).toBe(false);
+  });
+});