fix(ci): configure a git identity so the suite passes on a bare runner

[ccevans]

What this does

Makes CI green again. main has been failing since a3fe211 (runs #50 and #51), on all three matrix legs.

The failure is not in the product code — all 1208 tests pass locally, lint is clean, and npm ci resolves fine. It is three assertions in test/lib/project.test.js that require createProject's initial git commit to succeed:

• returns the facts a caller needs instead of printing them (L66)
• makes the initial commit (L84)
• reports the commit outcome as fields rather than as output (L158)

git commit needs an identity. A GitHub runner has no global git config, and the GIT_AUTHOR_*/GIT_COMMITTER_* vars the test sets in beforeEach never reach the child process — a Jest ESM test module mutates a copy of process.env, which the file's own comment above L150 already documents. On a developer machine git falls back to the global config and the commit lands, so the suite passes everywhere except a bare runner.

This adds a Configure git identity step to the workflow before Test.

Verification

Reproduced and confirmed by neutralising the global git config:

environment	result
GIT_CONFIG_GLOBAL=/dev/null (what CI has today)	3 failed, 10 passed
with a global identity (this change)	13 passed

Same three tests, same line numbers as the CI annotations.

Note on the alternative

The narrower fix is to have lib/project.js pass an explicit env to execSync, but that would paper over a real behaviour: on a machine with no identity, bobby new genuinely cannot commit, and the code already reports that correctly via committed: false / commitError. The tests are asserting the happy path, so the environment is what should supply the identity.

Checklist

• npm test passes
• npm run lint passes (0 errors, 37 pre-existing warnings)
• CHANGELOG.md not updated — happy to add a Fixed entry under [Unreleased] if you want build-infra changes logged there.