fix(hooks): use globalThis singleton for handler registry to survive bundle splitting

Without this fix, the bundler can emit multiple copies of internal-hooks
into separate chunks. registerInternalHook writes to one Map instance
while triggerInternalHook reads from another — resulting in hooks that
silently fire with zero handlers regardless of how many were registered.

Reproduce: load a hook via hooks.external.entries (loader reads one chunk),
then send a message:transcribed event (get-reply imports a different chunk).
The handler list is empty; the hook never runs.

Fix: use globalThis.__openclaw_internal_hook_handlers__ as a shared
singleton. All module copies check for and reuse the same Map, ensuring
registrations are always visible to triggers.

src/hooks/internal-hooks.ts

@@ -200,8 +200,23 @@ export interface InternalHookEvent {
 
 export type InternalHookHandler = (event: InternalHookEvent) => Promise<void> | void;
 
-/** Registry of hook handlers by event key */
-const handlers = new Map<string, InternalHookHandler[]>();
+/**
+ * Registry of hook handlers by event key.
+ *
+ * Uses a globalThis singleton so that registerInternalHook and
+ * triggerInternalHook always share the same Map even when the bundler
+ * emits multiple copies of this module into separate chunks (bundle
+ * splitting). Without the singleton, handlers registered in one chunk
+ * are invisible to triggerInternalHook in another chunk, causing hooks
+ * to silently fire with zero handlers.
+ */
+const _g = globalThis as typeof globalThis & {
+  __openclaw_internal_hook_handlers__?: Map<string, InternalHookHandler[]>;
+};
+if (!_g.__openclaw_internal_hook_handlers__) {
+  _g.__openclaw_internal_hook_handlers__ = new Map<string, InternalHookHandler[]>();
+}
+const handlers = _g.__openclaw_internal_hook_handlers__;
 const log = createSubsystemLogger("internal-hooks");
 
 /**