build: convert repo utility scripts to typescript

[gpbl]

This finishes the TypeScript migration for the small repo utility scripts that were still living in .mjs while the newer release scripts had already moved to TypeScript. The goal here is consistency only: keep the scripts folder on one runtime path without changing what these utilities do.

What Changed

• converted scripts/check-package-versions.mjs to scripts/check-package-versions.ts
• converted scripts/npm-pack-dry-run.mjs to scripts/npm-pack-dry-run.ts
• updated package.json to run these scripts, and release:ci, through node --import tsx instead of the tsx CLI

Review Notes

• behavior should stay the same; this is a script runtime cleanup, not a release-policy change
• I validated the converted commands directly with pnpm check:versions and pnpm pack:dry-run
• the pack:dry-run validation still shows the existing npm config warnings, but it now runs through the TypeScript script successfully

[changeset-bot]

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Latest commit: 2f28a07

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