AGENTS: add author-identity commit rule

[ptr727]

Summary

A fleet governance audit found this repo's AGENTS.md defined the signing rule and the default-to-staging rule, but was missing the author-identity rule (which account/identity a commit must use). The canonical template AGENTS.md now defines this rule; this PR adds it here for fleet consistency.

Change

One bullet added to the Git and Commit Rules section, immediately after the existing "All commits must be cryptographically signed" bullet:

Commit under the committing account's own GitHub noreply identity - never a private, personal, or invented address...

It codifies that author/committer must be the GitHub noreply of the signing account (ptr727@users.noreply.github.com for this fleet), to verify user.email before committing, and why a wrong identity matters (GH007 email-privacy push protection, polluted history), while noting identity is distinct from signing.

Notes

• Canonical wording inserted essentially verbatim, matching the existing bullet style.
• ASCII-only, US English, - hyphens (no em-dashes).
• File EOL (CRLF) preserved; zero mixed line endings.
• Commit is SSH-signed.

Co-Authored-By: Claude Opus 4.8 (1M context) noreply@anthropic.com

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 66.89%. Comparing base (322fd8a) to head (1dab546).

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #409   +/-   ##
========================================
  Coverage    66.89%   66.89%           
========================================
  Files           13       13           
  Lines         1160     1160           
  Branches       108      108           
========================================
  Hits           776      776           
  Misses         338      338           
  Partials        46       46           

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[Copilot]

Pull request overview

This PR updates the repo’s agent governance documentation by adding an explicit commit author-identity rule to the Git and Commit Rules section, aligning AGENTS.md with the canonical fleet template and clarifying the expected author/committer identity for agent-authored commits.

Changes:

• Add a new “GitHub noreply identity” rule requiring agent-authored commits to use the committing account’s GitHub noreply email (and to verify user.email before committing).
• Document why incorrect author identity is operationally problematic (GH007 privacy protection, polluted history) and how it relates to - but is distinct from - signing.