fix: ensure Telegram is always primary in identity links

When a Discord user linked Telegram via the Telegram Login Widget,
LinkIdentityAsync incorrectly made Discord primary and Telegram
secondary. This broke access to all Telegram groups/sessions because
ResolveEffectivePlayerIdAsync returned the (empty) Discord primary.

- In /auth/telegram callback, swap LinkIdentityAsync args so Telegram
  is always treated as the current (primary) account.
- Add V022 migration to reverse any existing incorrectly-oriented
  player_links where Discord is primary and Telegram is secondary.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/GmRelay.Web/Program.cs

@@ -137,9 +137,10 @@ app.MapGet("/auth/telegram", async (HttpContext context, TelegramAuthService aut
     {
         try
         {
+            // Always make Telegram the primary (it has the historical data/groups)
             await sessionStore.LinkIdentityAsync(
-                currentPlatform, currentExternalUserId,
                 "Telegram", telegramId.ToString(System.Globalization.CultureInfo.InvariantCulture),
+                currentPlatform, currentExternalUserId,
                 name);
             return Results.Redirect("/profile?linked=telegram");
         }