[codex] Add Eclipse release hygiene helpers

[mfoltz]

Summary

• add Eclipse release-nudge and bump-version helpers
• add fixture-based helper regression coverage
• bump Eclipse metadata and changelog to 1.3.15
• run the release hygiene gate during build verification

Validation

• pwsh .codex\scripts\release-hygiene.tests.ps1
• C:\Program Files\Git\bin\bash.exe .codex/scripts/version-metadata.sh
• git diff --check
• pwsh -NoProfile -File .codex\scripts\release-nudge.ps1 -WarnOnly
• dotnet build Eclipse.csproj --configuration Release -p:DeployToClient=false --no-restore

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 74e835a83d

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".