fix(ci): provision native build headroom

[riverpilot]

Summary

• retain PR fix(ci): make cluster release gates reproducible #125's reproducible cluster release gates
• align the Woodpecker native authority build with its asserted 6Gi memory limit
• align ephemeral storage with the asserted 12Gi limit

Supersedes #125.

Screenshots

No visual change.

Testing

• node --test scripts/cluster-ci/cluster-ci-contract.test.mjs (13 passed)

Risk

• The native build pod requests higher maximum cluster capacity.

Notes

• Rebased on current main.

AI Review Report

• Resolves the exact pipeline/contract mismatch reported by cluster and verify.

Security Audit

• No secrets, permissions, or registry policies changed.