fix(providers): retain worker cleanup owners through shutdown

Validation: integrated changes passed formatting, typecheck, lint, resolved module-boundary verification and git diff --check. Tests and real-provider workflows were not run.

src/application/javascript/JavaScriptRecoveryPort.ts

@@ -8,6 +8,7 @@ import type {
 
 /** Typed boundary for upstream source recovery without exposing its protocol. */
 export interface JavaScriptRecoveryPort {
+  close?(): Promise<void>;
   recover(
     input: JavaScriptRecoveryInput,
     options?: ExecutionOptions,