[hzqst]

GoldSrc_VibeSignatures v20261024a adds the unversioned decay identity. The synchronizer validates the complete upstream index before selecting manifest entries, so the old versioned-only rule rejects the release even when this component does not consume Decay.

Explicitly accept decay alongside the existing versioned tags and keep rejecting unknown unversioned or malformed tags. Add regression coverage for stable/content-addressed snapshot names and every manifest version-condition field.

The component manifest and its selected game versions are unchanged.

Validation:

• Python unittest discovery: Ran 4 tests in 0.013s; all passed. New tag tests reproduced the rejection before the fix.
• Verified the official release archive SHA-256 and parsed/validated its complete 27-snapshot index.
• Supplied the immutable release index and hash-verified cache to the production synchronizer entry point: 2 pruned snapshots passed the standalone manifest validator and CLI --validate-only.
• All 2 previously selected snapshots retain byte-identical pruned content.
• git diff --check passed. No native code changed; native builds and in-game behavior were not tested.