SW-110 — Add npm pack content snapshot test

[dDevAhmed]

Summary

Verify npm pack --dry-run includes only intended publish artifacts.

Acceptance Criteria

• packed file list is asserted deterministically;
• source/tests/workflows/secrets are excluded;
• no publish occurs;
• repository checks pass.

Dependencies

• SW-109

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🏷 Labels

• Stellar Wave
• type: test
• area: release
• priority: P0
• difficulty: medium
• points: 150
• workstream: release
• supply-chain