fix(release): unblock first oliphaunt release

[f0rr0]

Summary

Unblocks the first Oliphaunt release flow after the repo reset to 0.0.0.

What Changed

• Stops treating old unprefixed PGlite tags as legacy WASIX product tags, so the first Oliphaunt release starts from the current 0.0.0 manifest state.
• Removes the first-time registry package identity preflight from release publish dry-runs and the release workflow registry gate.
• Updates the release setup guide and metadata assertion to describe identity checks as optional setup diagnostics, not first-release gates.

Operational Cleanup

Cleared the stale autorelease: pending label from merged PR #60. That PR is no longer on current main, and Release Please was blocking new release PR creation because it still considered that old release PR pending.

Validation

• tools/release/release.py check
• tools/release/release.py plan --from-product-tags --include-current-tags --head-ref origin/main --format github-output
• tools/release/release.py check-registries --products-json '<planned products>' --head-ref origin/main
• tools/policy/check-workflows.sh
• git diff --check