feat(provisioning): game-account signup, admin email invites, unlink (2.0)

Phase 5: the account-provisioning backend — link-only stays, plus hybrid
self-signup, an admin email-invite tool, and site-side unlink.

- uoLinkClient.createAccount / unlinkAccount (v2). Password is forwarded to the
  shard (hashed there) and never stored/logged; the end-user browser IP is passed
  for the shard's per-IP cap; actor is stamped server-side.
- Hybrid signup: POST /player/shard/account provisions a game account (its own
  username + password) for the signed-in user and mirrors the link locally. Gated
  by the new game_account_signup setting AND the shard's own mode (mapped 403/409/
  429/400/503). Serves both self-serve signup and the invite-accept game step.
- Email invites: user_invites table (sha256 token hash, single-use, expiring);
  invites model + admin CRUD (POST/GET/DELETE /admin/invites, admin-only) +
  mailer.sendInvite (falls back to returning the accept link if email is off);
  public token-gated accept (GET /auth/invite/:token, POST .../accept) creates the
  user at the invite's preset role and logs them in, bypassing the registration
  gate. Accept is race-safe (atomic single-use; rolls back the user if it loses).
- Admin unlink: DELETE /admin/users/:id/shard/link/:account (admin-only) + local
  mirror drop; account.unlinked ingest reconciles the mirror when a player runs
  [unlink in game. account.audit / account.unlinked are logged (admin channel
  only — never on the public SSE allowlist).

Tests: invites model (hashing, single-use, expiry, revoke) + account.* ingest
reconcile/visibility. Full suite 193/193; swagger regenerated.

Refs .plans/protocol2-integration.md (Phase 5).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/test/shardIngest.protocol2.test.js

@@ -12,6 +12,7 @@ function makeDeps() {
     governorUpsert: [],
     presenceSet: [],
     houseRegistry: [], houseRemove: [],
+    linkRemove: [],
     appended: [], broadcast: [],
   }
   const noop = async () => {}
@@ -29,6 +30,7 @@ function makeDeps() {
       clearOnline: noop, upsertOnline: noop, setOffline: noop, upsertHouse: noop,
       addEconomySample: noop,
     },
+    shardLinks: { removeByAccount: async (account) => { calls.linkRemove.push(account) } },
     uoLinkConfig: { recordStatus: noop },
     broadcast: (ev) => { calls.broadcast.push(ev) },
     log: { warn() {}, info() {}, error() {} },
@@ -91,3 +93,27 @@ test('region.enter is broadcast-only — not logged, no state side effect', asyn
   assert.equal(deps.calls.appended.length, 0)
   assert.equal(deps.calls.broadcast.length, 1) // still surfaced live
 })
+
+test('account.unlinked reconciles the local link mirror and is logged', async () => {
+  const deps = makeDeps()
+  const r = await shardIngest.ingest(
+    { kind: 'account.unlinked', origin: 'in-game', account: 'bob', websiteUserId: '9931', t: 9 }, deps)
+  assert.deepEqual(deps.calls.linkRemove, ['bob']) // mirror dropped
+  assert.equal(r.logged, true) // provisioning audit trail
+  assert.equal(deps.calls.appended[0].kind, 'account.unlinked')
+})
+
+test('account.audit is logged (provisioning history) but has no state side effect', async () => {
+  const deps = makeDeps()
+  const r = await shardIngest.ingest(
+    { kind: 'account.audit', origin: 'web', action: 'create', actor: 'web:jane', target: 'bob', t: 10 }, deps)
+  assert.equal(r.logged, true)
+  assert.equal(deps.calls.linkRemove.length, 0)
+  assert.equal(deps.calls.appended[0].kind, 'account.audit')
+})
+
+test('account.audit / account.unlinked are NOT on the public SSE allowlist', () => {
+  const broadcast = require('../src/utils/shardBroadcast')
+  assert.equal(broadcast.PUBLIC_KINDS.has('account.audit'), false)
+  assert.equal(broadcast.PUBLIC_KINDS.has('account.unlinked'), false)
+})