Ensure errors don't cause silent failure, make authN failure messages friendlier

[jeri-temporal]

What was changed

• Moved CommandHarnes from integration-only commands_test.go to common_test.go so it could be used for unit tests as well
• Ensure failures are printed to stderr when error logging is disabled. This prevents the cloud CLI from failing silently
• Introduce the FriendlyError type as a means of marking error messages for direct display without appending the full error chain
• Use a custom interceptor to capture errors from within the gRPC call chain and wrap them around errors stored on the context struct. This allows errors.Is/errors.As to find FriendlyErrors that occur inside gRPC callback methods

Why?

Running commands while not logged in (including temporal cloud whoami) produces no output and a non-zero exit code, and other errors are similarly swallowed unless handled specifically within each command.

Checklist

1. Closes CLDDX-141

2. How was this tested:
   make, make test, make test-integration, verified that running commands like temporal cloud whoami or temporal cloud namespace list without being authenticated prints no login session found, please run `temporal cloud login`

3. Any docs updates needed?
   No

---

Note

Medium Risk
Changes global CLI failure handling and OAuth/API-key error propagation for all cloud commands, though behavior is limited to error display and wrapping with added unit tests.

Overview
Fixes silent non-zero exits when commands fail (e.g. unauthenticated whoami) by tightening the default Fail path: FriendlyError messages go to stderr without the full chain, and if error logging is off, the full error is still printed to stderr.

Auth/token failures in GetAPIKey now return FriendlyError (clear login/reset guidance) and stash the original error on the gRPC context via errorContext / grabOriginalErrorInterceptor + GraftErrors, so handlers can still use errors.Is / errors.As through gRPC-wrapped failures.

whoami uses GetCloudClient for consistency with other commands. Tests add CommandHarness reuse (moved out of integration-only file), subprocess checks that stderr is user-facing (not slog level=), and unit coverage for friendly errors and error grafting.

^{Reviewed by Cursor Bugbot for commit 0cd97f6. Bugbot is set up for automated code reviews on this repo. Configure here.}

[anekkanti]

bugbot run

[cursor]

✅ Bugbot reviewed your changes and found no new issues!

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 0cd97f6. Configure here.}

[anekkanti]

Whats the purpose of this change?