feat(links): unlink every Steam id before an account is deleted (MODULE_API 1.20.0)

ACCOUNT_DELETION.md §4.4 (AD10). api.onUserDeleting calls links.unlinkForDeletion,
which runs the player's own unlinkOwned per link, logs rust.account.unlink with
reason 'account deleted', and marks every server's permission sync dirty so the
withdrawn grants reach the game on the next tick. coreApi ^1.20.0; core-ref pinned
to website#232's merge (7bd93b8); engagement manifest regenerated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E14m6SuuY6i1vASFeGDBeY

server/index.js

@@ -168,6 +168,13 @@ module.exports = function register(ctx, api) {
   api.onIdentityLinking(links.checkSteamSignin)
   api.onIdentityLinked(links.linkFromSteamSignin)
 
+  // Account deletion (MODULE_API 1.20.0; ACCOUNT_DELETION.md §4.4, AD10). Core
+  // asks before the users row goes: every Steam id the account holds is unlinked
+  // through the player's own unlink, and the permission sync is marked dirty so
+  // the withdrawn grants reach the game on the next tick. It cannot stop the
+  // deletion, and never waits on a game.
+  api.onUserDeleting(links.unlinkForDeletion)
+
   // The public demo's seed (MODULE_API 1.18.0, DM15): the rig's server row and
   // demo-player's Steam link, written by this module from its part of the
   // fixture. Called only by `npm run seed:demo` on a DEMO_MODE deployment. The