chore(ci): prepare v2 legacy dist-tag

[rmi22186]

Summary

• Change the V2 npm dist-tag from the transitional latest mapping introduced by fix(ci): keep v2 releases on latest #1355 to legacy-v2-latest.
• Keep the V3 npm dist-tag mapped to latest.
• Update the approved V2 mapping assertion to match the future release behavior.

Merge timing and rollout

This draft is intentionally not for immediate merge. It is stacked on #1355 and should be merged only at the V3 cutover, after #1355 and the current final V2 release have landed. After #1355 merges, retarget this PR to master before merging it at cutover.

Before moving latest to V3, manually assign the legacy-v2-latest npm dist-tag to the last already-published V2 version. This workflow change only affects future publishes and does not retroactively tag existing package versions.

After cutover, future V2 releases will publish under legacy-v2-latest, while consumers using compatible V2 semver ranges will continue resolving V2 releases normally.

The identical workflow change must eventually reach main for master/main workflow parity before real release workflows run.

Validation

• YAML parsed successfully.
• All 26 embedded shell blocks passed bash -n.
• git diff --check passed.
• Confirmed the stacked diff changes exactly one file with only the two V2 mappings updated; V3 remains latest.
• npm's bundled semver parser returns null for legacy-v2-latest, confirming it is not a SemVer range and is acceptable as an npm dist-tag.

Safety

• No package was published and no npm dist-tag was mutated.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[rmi22186]

Closing as obsolete. The current paired release workflows intentionally keep v2 on latest and v3 on next; any future v3 latest cutover should be implemented as a fresh coordinated change across both release tracks.