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.

platform/telegram/internal/render/render_test.go

@@ -29,6 +29,17 @@ func nudgePayload(id string) []byte {
 	return b.FinishedBytes()
 }
 
+func namedNudgePayload(id, name string) []byte {
+	b := flatbuffers.NewBuilder(0)
+	gid := b.CreateString(id)
+	n := b.CreateString(name)
+	scrabblefb.NudgeEventStart(b)
+	scrabblefb.NudgeEventAddGameId(b, gid)
+	scrabblefb.NudgeEventAddSenderName(b, n)
+	b.Finish(scrabblefb.NudgeEventEnd(b))
+	return b.FinishedBytes()
+}
+
 func matchFoundPayload(id string) []byte {
 	b := flatbuffers.NewBuilder(0)
 	gid := b.CreateString(id)
@@ -164,6 +175,23 @@ func TestRenderGameEvents(t *testing.T) {
 	}
 }
 
+// TestRenderNudgeNamed checks the nudge body names the sender when present (both languages) and
+// falls back to the plain phrase — no stray format directive — when the name is absent.
+func TestRenderNudgeNamed(t *testing.T) {
+	en, ok := Render("nudge", namedNudgePayload(gameID, "Ann"), "en")
+	if !ok || !strings.Contains(en.Text, "Ann") {
+		t.Errorf("en named nudge %q should name the sender", en.Text)
+	}
+	ru, _ := Render("nudge", namedNudgePayload(gameID, "Аня"), "ru")
+	if !strings.Contains(ru.Text, "Аня") {
+		t.Errorf("ru named nudge %q should name the sender", ru.Text)
+	}
+	plain, _ := Render("nudge", nudgePayload(gameID), "en")
+	if plain.Text == "" || strings.Contains(plain.Text, "%s") {
+		t.Errorf("unnamed nudge %q should be the plain phrase, not a format string", plain.Text)
+	}
+}
+
 func TestRenderNotify(t *testing.T) {
 	cases := map[string]struct {
 		subKind string