Address feedback on localization guidance for automated PRs

[Copilot]

Summary of the Pull Request

This PR updates localization guidance to clarify that automated localization-service pull requests are exempt from the contributor-facing rule about filing issues instead of directly editing non-en-US localized files. It also updates branch ancestry so the PR diff only contains the guidance changes.

PR Checklist

• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

• Updated CONTRIBUTING.md localization guidance to explicitly exclude automated localization-service PRs generated by the localization pipeline.
• Updated .github/copilot-instructions.md localization guidance with the same exemption so automated PR handling is consistent.
• Merged origin/master into this branch so unrelated locale Resources.resw file changes from the stacked base are no longer included in this PR diff.
• This addresses the stacked PR feedback from: Localization change from build: 149610132 #40799 (comment)
• Original PR context: Localization change from build: 149610132 #40799

Validation Steps Performed

• Ran python3 tools/devops/validate-copyright-headers.py
• Ran python3 tools/devops/validate-localization.py
• Verified PR three-dot diff vs origin/master contains only:
  • CONTRIBUTING.md
  • .github/copilot-instructions.md

[benhillis]

@copilot - why are so many unrelated localization files in this pr? I just want the guidance so future localization update PRs don't get a million comments about "you shouldn't modify this file"

[Copilot]

@copilot - why are so many unrelated localization files in this pr? I just want the guidance so future localization update PRs don't get a million comments about "you shouldn't modify this file"

Those files were showing up because this branch was based before master absorbed localization commit #40799, so the PR three-dot diff still included them. I merged origin/master into this branch in d4add1a, and now the PR diff is only the two guidance files (CONTRIBUTING.md and .github/copilot-instructions.md).