Implement commits domain in GitHub simulator (/repos/{owner}/{repo}/commits*)

[Copilot]

The GitHub simulator exposed repository, issues, PRs, and workflows, but commit-focused endpoints were still random stubs. This PR adds stateful commit APIs so commit listing, ref lookup, statuses, and commit comments behave consistently with seeded repository state.

• Commits domain state + behavior (routes/repos/_.context.ts)

  • Added commit domain storage to RepoState:
    • commits (by SHA)
    • commitStatuses (by SHA)
    • commitComments (by SHA)
    • nextCommitCommentId
  • Added commit methods:
    • getCommit (supports branch refs, exact SHA, unique short-SHA prefix)
    • listCommits (newest-first, optional sha ref filter, pagination)
    • saveCommitStatus / listCommitStatuses
    • getCombinedStatus (derives aggregate state from statuses)
    • saveCommitComment / listCommitComments
  • Wired branch initialization to materialize branch HEAD commits into the repo commit map.

• Root context delegation (routes/_.context.ts)

  • Added forwarding methods for new commits APIs so route files can call $.context.* without domain-specific imports.

• HTTP route implementations (replacing random stubs)

  • Implemented:
    • GET /repos/{owner}/{repo}/commits
    • GET /repos/{owner}/{repo}/commits/{ref}
    • GET/POST /repos/{owner}/{repo}/commits/{commit_sha}/comments
    • GET /repos/{owner}/{repo}/commits/{ref}/status
    • GET /repos/{owner}/{repo}/commits/{ref}/statuses
  • Added repository existence checks and 404 behavior for missing repo/commit refs.

• Scenario seeding

  • Added commitStatuses scenario and invoked it from seedGitHub.
  • Seeds counterfact/actions-demo main HEAD with ci/lint and ci/test success statuses.

• Coverage updates

  • Extended context tests for commit resolution, pagination, combined status derivation, and commit comment creation.
  • Extended route tests for commit endpoints (happy path + 404s).

export const GET: reposGetCommit = async ($) => {
  const { owner, repo, ref } = $.path;
  if (!$.context.hasRepository(owner, repo)) return $.response[404].empty();

  const commit = $.context.getCommit(owner, repo, ref); // branch, SHA, or short SHA
  if (!commit) return $.response[404].empty();

  return $.response[200].json(commit);
};

[Copilot]

Pull request overview

This PR implements stateful commit-related endpoints for the GitHub simulator, replacing random stubs with repository-backed commit, status, and comment behavior.

Changes:

• Adds commit storage, ref resolution, status aggregation, and commit comment handling to the repos context.
• Wires root context delegation and route handlers for /repos/{owner}/{repo}/commits*.
• Seeds commit statuses for counterfact/actions-demo and adds route/context tests for the new behavior.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
github/routes/repos/_.context.ts	Adds commit domain state and behavior.
github/routes/_.context.ts	Forwards commit-related methods to repos context.
github/routes/repos/{owner}/{repo}/commits.ts	Implements commit listing route.
github/routes/repos/{owner}/{repo}/commits/{ref}.ts	Implements commit lookup by ref/SHA.
github/routes/repos/{owner}/{repo}/commits/{commit_sha}/comments.ts	Implements commit comment listing and creation.
github/routes/repos/{owner}/{repo}/commits/{ref}/status.ts	Implements combined commit status route.
github/routes/repos/{owner}/{repo}/commits/{ref}/statuses.ts	Implements commit status listing route.
github/scenarios/index.ts	Seeds default commit statuses.
github/test/routes.test.ts	Adds HTTP route coverage for commit endpoints.
github/test/repos.context.test.ts	Adds direct context coverage for commit behavior.
.github/todo/commits-v2.md	Removes completed implementation plan.

[pmcelhaney]

@copilot implement all suggested changes and add appropriate tests

[Copilot]

@copilot implement all suggested changes and add appropriate tests

Implemented all requested reviewer suggestions and added test coverage in commit 7690a94.

Included fixes:

• GET /repos/{owner}/{repo}/commits now defaults to the repository default branch when sha is omitted.
• Combined status now derives from the latest status per context.
• Status sorting now has stable latest-first tie-breaking when timestamps are equal.
• Commit statuses/comments list routes now pass page/per_page query params through to context pagination.
• Added context and route tests covering these behaviors.

[pmcelhaney]

@copilot refactor routes tests to test through HTTP like the tests in swagger-pet-store do

[Copilot]

@copilot refactor routes tests to test through HTTP like the tests in swagger-pet-store do

Implemented in commit 0db6e41. I refactored the commit route tests in github/test/routes.test.ts to exercise the routes via HTTP requests (including pagination and 404 cases) using a local HTTP test harness, instead of calling route handlers directly.