Add planned 0.3.120 development assets

[acedward]

Summary

• add exact planned metadata for 31 development-only payloads from Actions artifact 9696849345
• keep all 66 published release entries byte-identical
• update synthetic test fixtures to explicitly build from the published-only catalog base

No release assets are uploaded by this PR.

Verification

• scripts/validate-catalog --previous-catalog ... — PASS, 97 entries
• full network-disabled/read-only Docker test suite — PASS, 43/43
• git diff --check and credential/material scans — PASS