fix(release): make npm publish retries idempotent - #426

Summary

• Route publish:next and publish:latest through a retry-safe scripts/publish.ts wrapper.
• Skip immutable npm publish when allagents@version already exists.
• Ensure the requested npm dist-tag points at the release version without moving tags backwards.

Testing

• bun install --frozen-lockfile
• bun build scripts/publish.ts --target=bun --outfile=/tmp/allagents-publish-check.js
• bun run typecheck
• bun run lint
• bun run publish:next on already-published 1.12.0-next.1 verified the idempotent skip path
• bun test (1314 pass, 4 skip)
• pre-push hook passed lint, typecheck, and tests

Post-Deploy Monitoring & Validation

• After merge, dispatch Publish with channel=existing and ref=v1.12.0-next.1.
• Healthy signal: workflow succeeds, reports package already published, and confirms allagents@next points to 1.12.0-next.1.
• Failure signal: npm duplicate-version error or trusted-publishing auth error; rollback by reverting this PR and the publish workflow consolidation if needed.
• Validation window: immediate post-merge workflow run; owner: release operator.