fix(local-cluster): make destroy-all cleanup portable across POSIX shells

[mikeyrcamp]

Summary

make -C tools/ncp-local-cluster destroy-all-ncp-local fails on systems where Make uses a POSIX /bin/sh that does not implement Bash's pipefail option. The target currently executes set -o pipefail without selecting Bash.

This prevents the repository-documented deterministic cleanup command from running on common Debian/Ubuntu environments where /bin/sh is dash, including the no-clusters-present case.

Reproduction

At current main revision 603059d81a3adc4f134866dbb0f678b053e59e0c:

$ /bin/sh -c 'set -o pipefail'
/bin/sh: 1: set: Illegal option -o pipefail

$ make -C tools/ncp-local-cluster destroy-all-ncp-local
/bin/sh: 1: set: Illegal option -o pipefail
make: *** [Makefile:156: destroy-all-ncp-local] Error 2

The failure is deterministic and occurs before the target can inspect the k3d cluster list.

Expected behavior

The target should either:

• use only POSIX-shell syntax; or
• explicitly execute the recipe with Bash when pipefail is required.

It should successfully report that no matching clusters exist when the inventory is empty, and should preserve failure detection for the k3d cluster list pipeline.

Acceptance criteria

• destroy-all-ncp-local succeeds with the repository's documented prerequisites on a system where /bin/sh is dash.
• An empty cluster inventory exits successfully.
• A populated inventory deletes all and only ncp-local* clusters.
• A failure from k3d cluster list or jq remains visible rather than being silently treated as an empty inventory.
• Focused automated coverage protects the shell contract.

Context

Discovered while performing fresh end-to-end validation for #1075. The validation was stopped at this first unexpected cleanup failure; no workaround was used to represent the documented path as passing.

[mikeyrcamp]

Implemented in #1263.

Sanitized verification evidence:

• Base revision: 603059d81a3adc4f134866dbb0f678b053e59e0c

• Fix revision: 4c100cf51b0a8623f39009e393435c86c96d55df

• RED on the unmodified base in a fresh sparse worktree on Ubuntu, where /bin/sh resolves to /usr/bin/dash:

  $ MAKE_SHELL=/bin/sh ./tests/test-destroy-all-ncp-local.sh
  /bin/sh: 1: set: Illegal option -o pipefail
  make: *** [Makefile:156: destroy-all-ncp-local] Error 2
  FAIL: empty cluster inventory should succeed under /bin/sh

• GREEN on the fix under the same Dash environment:

  $ MAKE_SHELL=/bin/sh make -C tools/ncp-local-cluster test-destroy-all-ncp-local
  PASS: destroy-all-ncp-local Makefile tests

• The focused test uses controlled k3d and jq executables. It verifies empty-inventory success, deletion of only selected ncp-local* names, and nonzero propagation from both inventory stages. It does not create or destroy real clusters.

• Broader checks passed: make validate-compute-clusters, make print-compute-clusters, make test-multicluster-make, bash -n tools/ncp-local-cluster/tests/test-destroy-all-ncp-local.sh, shellcheck tools/ncp-local-cluster/tests/test-destroy-all-ncp-local.sh, and git diff --check.

[mikeyrcamp]

PR #1263 is now terminal green on exact head 4c100cf51b0a8623f39009e393435c86c96d55df.

Automatic results include successful root Bazel build/tests, required Bazel checks, Go tools, docs, Helm charts, generated dependency documentation, dependency/license audits, secret scan, and CodeRabbit. CodeRabbit reported minimal merge risk and no actionable code findings or inline review threads. The PR is mergeable and awaits maintainer review; it has not been merged.