fix(slack): time out stalled external file uploads (#103442)

* fix(slack): time out stalled external file uploads

* fix(slack): scope external upload timeout

* fix(slack): restrict external upload transport

* fix(slack): restrict external upload transport

* fix(slack): preserve external upload retry safety

* test(slack): use compatible guarded fetch runtime

* test(plugin-sdk): update public export baseline

* fix(slack): harden external upload delivery

* refactor(slack): isolate upload completion

Keep ordinary Enterprise Grid traffic on the Bolt listener client. Use a team-scoped no-retry client only for one-shot external upload completion, while preserving the bounded raw-upload timeout and safe durable replay classification.

* fix(slack): refresh upload release metadata

* chore(slack): leave release notes release-owned

* fix(slack): classify failed uploads before completion

* fix(slack): keep upload completion untimed

* test(plugin-sdk): refresh public export baseline

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

src/cli/send-runtime/channel-outbound-send.ts

@@ -27,7 +27,7 @@ type RuntimeSendOpts = {
   gatewayClientScopes?: readonly string[];
   /** @internal Opaque durable intent id for provider-side reconciliation. */
   deliveryQueueId?: string;
-  /** @internal Refresh durable timing after provider serialization and before I/O. */
+  /** @internal Refresh durable timing before recipient-visible or finalizing platform I/O. */
   onPlatformSendDispatch?: () => Promise<void>;
   textMode?: "markdown" | "html";
 };