Fix CI: set git identity env vars in auto-init test

CI runners have no global `user.email`/`user.name`, so the auto-
inited nested repo couldn't commit. Pre-existing tests pass because
they `git init` + `git config user.email/name` on the nested repo
themselves; the new test relies on `_ensure_nested_git_repo` to
create the repo, so identity must come from env.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ryan-williams

tests/test_create.py

@@ -151,6 +151,12 @@ def test_create_issue_succeeds_with_gh_gitignored(self, tmp_path, monkeypatch):
         (draft_dir / 'DESCRIPTION.md').write_text('# Test Issue\n\nBody\n')
 
         monkeypatch.chdir(draft_dir)
+        # Identity for the nested repo `_ensure_nested_git_repo` will create
+        # (CI runners have no global git config)
+        for var in ('GIT_AUTHOR_EMAIL', 'GIT_COMMITTER_EMAIL'):
+            monkeypatch.setenv(var, 't@example.com')
+        for var in ('GIT_AUTHOR_NAME', 'GIT_COMMITTER_NAME'):
+            monkeypatch.setenv(var, 'T')
 
         from ghpr.commands import create as create_mod