fix(gateway): track deferred-platform load ownership per flow, not thread

A plugin's register() runs on a plugin-load deadline worker. When it re-walks
the platform registry (i18n/YAML layering -> plugin_entries()), _resolve sees
its own parent's in-flight loader, but ownership was keyed on
threading.get_ident() -- the parent's thread, not the worker -- so the nested
walk event.wait()ed on itself until the deadline abandoned the load (#130575).

Record in-flight load keys in a per-registry ContextVar instead. Deadline
workers start from copy_context(), so a nested walk on the parent's worker
takes the existing "recursively requested while loading" return, while
unrelated concurrent loaders (fresh contexts) still wait on the event.

gateway/platform_registry.py

@@ -7,6 +7,7 @@ registry first, then the legacy built-in path. Plugin side: ``platform_registry
 .register(PlatformEntry(...))``; gateway side: ``create_adapter("irc", platform_config)``.
 """
 
+import contextvars
 import logging
 import sys
 import threading
@@ -126,7 +127,11 @@ class PlatformRegistry:
         self._scoped_deferred: dict[str, dict[str, _Loader]] = {}
         self._inflight: dict[_LoadKey, threading.Event] = {}
         self._inflight_loaders: dict[_LoadKey, _Loader] = {}
-        self._inflight_owners: dict[_LoadKey, int] = {}
+        # Load keys whose loader is running in the current flow; copied into plugin deadline
+        # workers, so a nested walk from register() sees its own parent's load as recursive.
+        self._loading: contextvars.ContextVar[frozenset[_LoadKey]] = contextvars.ContextVar(
+            f"platform_registry_loading_{id(self)}", default=frozenset()
+        )
         self._cancelled_inflight: set[_LoadKey] = set()
         # A failed loader is no longer discoverable, but its identity remains
         # until ownership teardown can CAS-restore the displaced predecessor.
@@ -224,11 +229,10 @@ class PlatformRegistry:
                 event = threading.Event()
                 self._inflight[load_key] = event
                 self._inflight_loaders[load_key] = loader
-                self._inflight_owners[load_key] = threading.get_ident()
                 is_loader = True
             if event is None:
                 return
-            if not is_loader and self._inflight_owners.get(load_key) == threading.get_ident():
+            if not is_loader and load_key in self._loading.get():
                 logger.warning("Deferred platform '%s' recursively requested while loading", name)
                 return
         if not is_loader:
@@ -237,11 +241,13 @@ class PlatformRegistry:
             # we waited for; resolve that predecessor instead of a one-shot false negative.
             self._resolve(name, active_scope)
             return
+        token = self._loading.set(self._loading.get() | {load_key})
         try:
             loader()
         except Exception as e:
             logger.warning("Deferred load of platform '%s' failed: %s", name, e, exc_info=True)
         finally:
+            self._loading.reset(token)
             with self._lock:
                 was_cancelled = load_key in self._cancelled_inflight
                 entries, deferred = self._scope_maps(load_key[0])
@@ -249,7 +255,6 @@ class PlatformRegistry:
                     self._consumed_loaders[load_key] = loader
                 self._inflight.pop(load_key, None)
                 self._inflight_loaders.pop(load_key, None)
-                self._inflight_owners.pop(load_key, None)
                 self._cancelled_inflight.discard(load_key)
                 event.set()
         if was_cancelled:

tests/gateway/test_platform_registry.py

@@ -677,3 +677,26 @@ class TestMigratedPlatformWiring:
                 "probe and the active installer — status displays would "
                 "pip-install as a side effect"
             )
+
+
+def test_registry_walk_from_plugin_load_worker_does_not_wait_on_parent(monkeypatch):
+    """register() re-walking the registry on its deadline worker must not block on its own load."""
+    from hermes_cli import plugins_loader
+
+    monkeypatch.setattr(plugins_loader, "_resolve_plugin_load_timeout", lambda: 0.5)
+    reg = PlatformRegistry()
+    abandoned = []
+
+    class Ctx:
+        def _abandon_load(self):
+            abandoned.append(True)
+
+    def register():
+        reg.plugin_entries()
+        reg.register(PlatformEntry(name="reentrant", label="Re-entrant", adapter_factory=lambda cfg: None,
+                                   check_fn=lambda: True, source="plugin"))
+
+    reg.register_deferred("reentrant", lambda: plugins_loader.run_with_load_deadline("reentrant", Ctx(), register))
+
+    assert [e.name for e in reg.plugin_entries()] == ["reentrant"]
+    assert abandoned == []