…3456) (NVIDIA#3520)

> **Draft for visibility.** Issue-autopilot Stages 4-5 of NVIDIA#3456. Will
mark ready once batch self-review + CI complete.

## Summary

Closes the two remaining output threads in NVIDIA#3456 after the core
dead-loop fix already landed on `main` (via NVIDIA#3459, NVIDIA#3434, NVIDIA#3483). Full
sub-bug mapping in the [NVIDIA#3456 status
comment](NVIDIA#3456 (comment)).

- **Sub-bug #3** — `nemoclaw <name> destroy --yes` recovery hint
replaced with a registry-aware helper.
- **Sub-bug NVIDIA#4** — `Destroyed gateway 'nemoclaw' skipped`
self-contradictory wording replaced with `Gateway 'nemoclaw' already
removed or unreachable`.

## Acceptance criteria mapping

| Sub-bug | Resolution | Evidence |
|---|---|---|
| #1 dead loop | Already fixed on main (NVIDIA#3459) | out of scope |
| #2 firewall diagnostic | Already fixed on main (NVIDIA#3459) | out of scope
|
| **#3** literal `<name>` placeholder | **This PR** |
`src/lib/onboard/gpu-recovery.ts` + `onboard.ts:10387-10405` |
| **NVIDIA#4** misleading "skipped" wording | **This PR** |
`src/lib/actions/uninstall/run-plan.ts:210-228, 407-414` |
| NVIDIA#5 uninstall residuals | Already fixed on main (NVIDIA#3483) | out of scope
|

## Behavior matrix

`gpuPassthroughRecoveryLines(names)`:

| Input | Suggestion |
|---|---|
| `null` / `[]` | `nemoclaw uninstall && nemoclaw onboard --gpu` |
| one sandbox | `nemoclaw <name> destroy --yes --cleanup-gateway &&
nemoclaw onboard --gpu` |
| many sandboxes | each `destroy --yes`, only the last gets
`--cleanup-gateway` |

## Test plan

```
npm run typecheck:cli
npx vitest run src/lib/onboard/gpu-recovery.test.ts src/lib/actions/uninstall/run-plan.test.ts
```

22 tests pass (6 new + 16 existing).

## Notes for reviewers

- This is the work [NVIDIA#3464
attempted](NVIDIA#3464); that PR was
closed without merging after CodeRabbit asked for the `<name>`
placeholder to be forbidden in tests via negative assertion. This PR
adopts that refinement.
- `runOptional` extension is backwards-compatible — existing callers
without `onSkip` get the original wording.

Closes NVIDIA#3456 once merged.

---------

Signed-off-by: Charan Jagwani <charjags100@gmail.com>
Co-authored-by: Charan Jagwani <charjags100@gmail.com>
Co-authored-by: Carlos Villela <cvillela@nvidia.com>