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>

scripts/plugin-sdk-surface-report.mjs

@@ -195,7 +195,7 @@ export function readPluginSdkSurfaceBudgets(env = process.env) {
     ),
     publicExports: readPluginSdkSurfaceBudgetEnv(
       "OPENCLAW_PLUGIN_SDK_MAX_PUBLIC_EXPORTS",
-      10492,
+      10493,
       env,
     ),
     publicFunctionExports: readPluginSdkSurfaceBudgetEnv(