chore(release): configure Editor V0 maintenance

[dancormier]

Summary

• configure v0 as the protected Editor 0.15.x maintenance line
• publish maintenance releases under legacy-v0 without changing npm or GitHub Latest
• reject versions outside stable 0.15.x and unsafe SemVer-like npm tags
• add CODEOWNERS and release-configuration coverage
• verified with build, lint, 1,092 unit tests, 195 Playwright tests, and six release-configuration tests
• no product behavior or accessibility changes

Jira

STACKS-856

Release safety

V0 publication validates the package version and npm dist-tag before publishing. GitHub Release creation is disabled for this maintenance line.

Changeset

Not required. This configures release infrastructure without changing the published package.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 7334557

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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