chore(release): prepare EMP v4.0.1

[ckken]

Scope

• Changed areas: root plus 17 core @empjs package versions, release contract assertion, 4.0.1 changelog, and version-specific release cover.
• Protected areas not touched: publish workflow, apps, website, packages/cdn-, and packages/lib- version lines.
• User-visible behavior: prepares the stable 4.0.1 package set for npm latest and GitHub Release.

Directory Boundary Check

• No apps or website changes.
• No packages/cdn-* or packages/lib-* version changes.
• No repo-local historical workflow directories.
• No generated build outputs, caches, or local indexes committed.

Validation

• corepack pnpm install --frozen-lockfile
• corepack pnpm workflow:check
• corepack pnpm test:rules (50/50)
• corepack pnpm release:check (17 internal, 10 independent)
• corepack pnpm ci:verify
• corepack pnpm empbuild
• corepack pnpm test:browser:all (22 files, 31 tests)
• corepack pnpm release:publish:dry -- --skip-build --force-all --tag latest (17/17)
• Independent release-scope and npm availability verification
• git diff --check

Release Safety

• Production publishing remains gated by the existing trusted publish workflow.
• Release scope excludes apps, website, CDN packages, and legacy lib packages.
• All 17 target package versions are currently unoccupied on npm.

Review

• Reviewer can reproduce the commands above.
• After merge, run publish workflow dry-run, then production with confirm_publish=4.0.1, force_all=true, tag=latest; verify npm readback before creating GitHub Release.