Align stable Action guidance with v0.5.3

[hzw0813]

Summary

• update the published-Action smoke job from v0.5.2 to the already-released v0.5.3 tag and assert the v0.5.3 runtime string
• update README and GitHub Actions/troubleshooting guidance to v0.5.3
• replace the old immutable release SHA with the v0.5.3 release commit d5fe3da78400a1b4d4154c0ddd9b84c3ef662e06
• record the release-consistency fix in Unreleased changelog notes

Why

v0.5.3 is already a public GitHub release, but the repository still told users to install @v0.5.2 and the main-branch published-Action smoke continued validating v0.5.2. That leaves the newest public Action outside the permanent post-release smoke gate and makes current integration guidance stale.

The v0.5.3 annotated tag resolves to release commit d5fe3da78400a1b4d4154c0ddd9b84c3ef662e06, so the security-sensitive full-SHA example now points to the same release as the stable tag guidance.

Verification

• full npm test passed after the documentation changes
• the final branch diff contains only the permanent CI/docs/changelog updates; temporary updater workflow files were removed
• PR CI will validate the source tree and workflow changes; after merge, the main-branch-only published Action smoke will exercise hzw0813/proofdiff@v0.5.3 directly