fix(filesystem): retain stable hash cleanup owners across callers

Preserve completed digests and primary failures when descriptor close fails.
Carry the exact handle owner through provider, readiness, cache, doctor and
verifier boundaries, and retry cleanup without rehashing or retrying a raw fd.
Close candidate-owned resources even when no target client was opened.
Keep verifier workspaces when provider shutdown remains incomplete.

Refs #4266

src/application/binary/SessionProviderRouter.ts

@@ -70,6 +70,11 @@ export class SessionProviderRouter {
     return this.route;
   }
 
+  /** Close provider owners not represented by the currently bound client. */
+  closeOwnedResources() {
+    return this.registry.closeOwnedResources();
+  }
+
   /** Resolve target routes before any provider client is created. */
   async resolve(
     target: BinaryTarget,