feat(phase1): rebrand to TTRPG Player and drop Git updates feed

Rename product to TTRPG Player (TTRPGPlayer / com.ttrpgplayer.app), use .ttrpg.zip for new saves while keeping .dnd.zip import, accept TTRPG- and DND- license keys on client, and remove sync-update-feed plus CI push to DndGamePlayerUpdates.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/shared/appBranding.ts

@@ -0,0 +1,13 @@
+/** Отображаемое имя продукта (с пробелом), не путать с `productName` сборки (`TTRPGPlayer`). */
+export const APP_DISPLAY_NAME_EN = 'TTRPG Player';
+export const APP_DISPLAY_NAME_RU = 'НРИ Плеер';
+
+/** Системный идентификатор приложения (exe, AppImage, appId). */
+export const APP_PRODUCT_NAME = 'TTRPGPlayer';
+export const APP_BUNDLE_ID = 'com.ttrpgplayer.app';
+
+export function appDisplayNameForLocale(localeTag: string): string {
+  const tag = localeTag.trim().toLowerCase();
+  if (tag.startsWith('ru')) return APP_DISPLAY_NAME_RU;
+  return APP_DISPLAY_NAME_EN;
+}