chore: configure release-it

[V3RON]

Summary

• add release-it with Conventional Commit changelog support
• guard releases to clean, tracked main and create GitHub releases/tags
• explicitly disable npm publication and document the release command

Verification

• pnpm install --frozen-lockfile --ignore-scripts
• pnpm check
• pnpm release --dry-run --ci --no-github --no-git.push --no-git.requireBranch --no-git.requireCleanWorkingDir
• pnpm audit --prod --audit-level=high