fix(release): isolate native client build caches

[jeremi]

Summary

The candidate builds Python wheels and Node bindings sequentially in the release profile. Their Zig compiler wrappers have different paths, so sharing Cargo's target directory makes the Node build reconfigure AWS-LC-FIPS inside Python's existing CMake cache and fail.

Give each language its own target directory while retaining reuse across products within that language. Restrict the cache paths and use a fresh namespace so an older shared target tree cannot be restored into this recipe.

Evidence

• python3 -m unittest release/scripts/test_release_workflow_structure.py: 56 tests passed, including target-directory isolation and cache migration assertions.
• Pinned actionlint: passed.
• python3 release/scripts/check-gates-inventory.py: passed, 213 gates.
• git diff --check: passed.
• The failed candidate's Python wheels and smoke passed before Node failed in AWS-LC-FIPS CMake reconfiguration. This change has not yet completed a real candidate build; the next candidate will exercise the corrected sequence on all supported rows.

Notes

This changes build-cache ownership only. Compiler versions, release profiles, dependencies, FIPS selection, and artifact verification are unchanged. The existing rehearsal builds Node independently and does not exercise this sequential-build failure.

DCO

• Every commit includes a Signed-off-by trailer.
• I reviewed the submitted changes and am responsible for the contribution.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-22T12:49:38.687092Z	d0ccd00	PR opened

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