fix(gateway): harden multiplex credential cluster salvage

Follow-ups on top of the cherry-picked cluster commits:

- slack: scope-authoritative app-token read — get_secret() with a
  narrow UnscopedSecretError fallback to os.getenv. Keeps @kohoj's
  correct semantics (scoped profile can never silently inherit the
  default profile's Socket Mode app) while fixing the regression where
  the default-profile startup loop and background reconnect rebuild,
  which call connect() unscoped under multiplex, would raise and
  fail-loop. Supersedes the 'or os.getenv' variant from #64461 which
  reintroduced the cross-profile fallback leak.
- test: unscoped-multiplex fallback regression test for connect().
- run.py: convert the last legacy self.adapters.get(source.platform)
  site (_rename_discord_auto_thread) to _adapter_for_source(source)
  so profile-routed Discord sources rename threads on the right
  adapter (from #57417's sweep).
- AUTHOR_MAP entry for @aguung.

gateway/run.py

@@ -14090,7 +14090,7 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
         """Best-effort semantic rename of a newly auto-created Discord thread."""
         if not await asyncio.to_thread(self._is_discord_auto_thread_lane, source):
             return
-        adapter = self.adapters.get(source.platform) if getattr(self, "adapters", None) else None
+        adapter = self._adapter_for_source(source) if getattr(self, "adapters", None) else None
         if adapter is None:
             return
         rename_thread = getattr(adapter, "rename_thread", None)

scripts/release.py

@@ -45,6 +45,7 @@ ACP_REGISTRY_MANIFEST = REPO_ROOT / "acp_registry" / "agent.json"
 
 # Auto-extracted from noreply emails + manual overrides
 AUTHOR_MAP = {
+    "agungsubastian1963@gmail.com": "aguung",  # PR #64461 salvage (gateway: multiplex secret_scope for authz/Slack/webhooks)
     "doogie@spark.local": "SAMBAS123",  # PR #64986 salvage (gateway: multiplex primary bot token scope)
     "emrekoca2003@gmail.com": "kocaemre",  # PR #36051 salvage (docs: audit round 3 code/doc reconciliation)
     "205466933+wesleion@users.noreply.github.com": "wesleion",  # PR #36049 salvage (telegram: per-topic free-response allowlist)

tests/gateway/test_slack.py

@@ -330,6 +330,73 @@ class TestAppMentionHandler:
         assert created_handlers
         assert created_handlers[0].app_token == "xapp-profile"
 
+    @pytest.mark.asyncio
+    async def test_connect_unscoped_multiplex_falls_back_to_env(self):
+        """Default-profile connect (multiplex active, NO scope installed) must
+        fall back to process env instead of raising UnscopedSecretError —
+        the primary startup loop and background reconnect rebuild both call
+        connect() unscoped (#59739 salvage follow-up)."""
+        config = PlatformConfig(enabled=True, token="xoxb-default")
+        adapter = SlackAdapter(config)
+
+        def _noop_decorator(_matcher):
+            def decorator(fn):
+                return fn
+
+            return decorator
+
+        mock_app = MagicMock()
+        mock_app.event = _noop_decorator
+        mock_app.command = _noop_decorator
+        mock_app.action = _noop_decorator
+        mock_app.client = AsyncMock()
+
+        mock_web_client = AsyncMock()
+        mock_web_client.auth_test = AsyncMock(
+            return_value={
+                "user_id": "U_DEFAULT",
+                "user": "defaultbot",
+                "team_id": "T_DEFAULT",
+                "team": "DefaultTeam",
+            }
+        )
+
+        created_handlers = []
+
+        class FakeSocketModeHandler:
+            def __init__(self, app, app_token, proxy=None):
+                self.app = app
+                self.app_token = app_token
+                self.proxy = proxy
+                self.client = MagicMock(proxy=None)
+                created_handlers.append(self)
+
+            async def start_async(self):
+                return None
+
+            async def close_async(self):
+                return None
+
+        secret_scope.set_multiplex_active(True)
+        try:
+            with (
+                patch.object(_slack_mod, "AsyncApp", return_value=mock_app),
+                patch.object(_slack_mod, "AsyncWebClient", return_value=mock_web_client),
+                patch.object(
+                    _slack_mod, "AsyncSocketModeHandler", FakeSocketModeHandler
+                ),
+                patch.dict(os.environ, {"SLACK_APP_TOKEN": "xapp-default"}),
+                patch("gateway.status.acquire_scoped_lock", return_value=(True, None)),
+                patch("asyncio.create_task", side_effect=_fake_create_task),
+            ):
+                result = await adapter.connect()
+        finally:
+            secret_scope.set_multiplex_active(False)
+
+        assert result is True
+        assert created_handlers
+        assert created_handlers[0].app_token == "xapp-default"
+
 
 class TestSlackConnectCleanup:
     """Regression coverage for failed connect() cleanup."""