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.ts

@@ -12,6 +12,29 @@ export function isMyTurn(game: GameView, myId: string): boolean {
   return (game.status === 'active' || game.status === 'open') && !!me && game.toMove === me.seat;
 }
 
+/** LobbyPhase is a game's lobby bucket — which of the three card sections it currently sits in. */
+export type LobbyPhase = 'mine' | 'theirs' | 'finished';
+
+/**
+ * gamePhase reports a game's lobby bucket for myId: 'finished' for any non-active/open status,
+ * else 'mine' when it is the caller's turn, else 'theirs'. It mirrors groupGames' partition and
+ * drives the per-card blink, which fires when a card transitions into 'mine' or 'finished'.
+ */
+export function gamePhase(game: GameView, myId: string): LobbyPhase {
+  if (game.status !== 'active' && game.status !== 'open') return 'finished';
+  return isMyTurn(game, myId) ? 'mine' : 'theirs';
+}
+
+/**
+ * shouldBlink reports whether a card's bucket change should fire the attention blink: only a
+ * transition into 'mine' (it became your turn) or 'finished' (the game ended) does — an
+ * opponent's-turn change is in-place. A first observation (prev === undefined) never blinks, so a
+ * cold render and games arriving from another screen stay quiet.
+ */
+export function shouldBlink(prev: LobbyPhase | undefined, next: LobbyPhase): boolean {
+  return prev !== undefined && prev !== next && (next === 'mine' || next === 'finished');
+}
+
 /** LobbyGroups holds the three ordered lobby sections. */
 export interface LobbyGroups {
   yourTurn: GameView[];