## Summary

The e2e test harness sources `~/.bashrc` to pick up the
freshly-installed `nemoclaw` CLI, but on images whose `.bashrc` resets
`PATH` (or unconditionally prepends system paths) this wipes the
`~/.local/bin` entry that `install.sh` just added, breaking every
downstream `nemoclaw ...` invocation. This PR re-adds `~/.local/bin` to
`PATH` after `.bashrc` sourcing and extracts the pattern into a shared
helper so it stays consistent as more scripts adopt it.

## Related Issue

Supersedes #3156 (cherry-picked with author credit preserved to Hung
Le).

## Changes

- **Fix (cherry-picked from #3156, attribution preserved):** re-add
`~/.local/bin` to `PATH` after sourcing `~/.bashrc` in the cloud e2e
test scripts, so the installed `nemoclaw` CLI remains resolvable on
images whose `.bashrc` rewrites `PATH`.
- **Refactor:** extract the PATH-refresh pattern into
`test/e2e/lib/install-path-refresh.sh` with two helpers:
- `nemoclaw_refresh_install_env` — source `.bashrc` then guarantee
`~/.local/bin` is on `PATH`
- `nemoclaw_ensure_local_bin_on_path` — idempotent prepend of
`~/.local/bin`
- Migrate 6 scripts (4 PR-touched + 2 adjacent references) to the
helper: `test-cloud-inference-e2e.sh`, `test-cloud-onboard-e2e.sh`,
`test-credential-migration.sh`, `test-deployment-services.sh`,
`test-diagnostics.sh`, `test-network-policy.sh`.
- Net diff: +67 / −33 lines across 7 files (including the new 41-line
helper).

**Follow-up (not in this PR):** ~23 additional e2e scripts also carry a
copy of the inline `.local/bin on PATH` guard. Intentionally left out to
keep this PR scoped to the scripts flagged in the original review.
Tracked in #3201.

## Type of Change

- [x] Code change (feature, bug fix, or refactor)
- [ ] Code change with doc updates
- [ ] Doc only (prose changes, no code sample modifications)
- [ ] Doc only (includes code sample changes)

## Verification

- [x] `npx prek run --all-files` passes
- [ ] `npm test` passes
- [x] Tests added or updated for new or changed behavior
- [x] No secrets, API keys, or credentials committed
- [ ] Docs updated for user-facing behavior changes
- [ ] `make docs` builds without warnings (doc changes only)
- [ ] Doc pages follow the [style
guide](https://github.com/NVIDIA/NemoClaw/blob/main/docs/CONTRIBUTING.md)
(doc changes only)
- [ ] New doc pages include SPDX header and frontmatter (new pages only)

**Verification notes:**
- `bash -n` syntax check passes on the new helper and all 6 migrated
scripts.
- Helper is sourceable via all three patterns the scripts use: `dirname
"${BASH_SOURCE[0]}"/lib/`, `${E2E_DIR}/lib/`, and
`${SCRIPT_DIR_TIMEOUT}/lib/`.
- Functional test of `nemoclaw_ensure_local_bin_on_path` confirmed:
prepends `~/.local/bin` when missing, is idempotent when already
present.
- Zero inline leftovers of the old pattern in the 6 migrated scripts.
- `npm test` has 18 unrelated timeout failures in
`test/install-preflight.test.ts` (installer integration suite) on this
machine; this PR does not touch that file (0 diff lines against it) and
does not modify any code path it exercises. The actual e2e scripts
changed here run in the Brev cloud suite, which is out of the `npm test`
scope.

---
Signed-off-by: Julie Yaunches <jyaunches@nvidia.com>

---------

Signed-off-by: Hung Le <hple@nvidia.com>
Signed-off-by: Julie Yaunches <jyaunches@nvidia.com>
Co-authored-by: Hung Le <hple@nvidia.com>