feat(engine): push run branch to remote on loop_restart

[mvanhorn]

Summary

• Adds optional git.push_remote config field to run config
• Pushes the run branch to the configured remote on each loop_restart (before starting fresh iteration) and on terminal outcome persistence
• Push is best-effort: failures are logged as warnings + progress events (git_push_start, git_push_ok, git_push_failed) but never abort the run
• Adds gitutil.PushBranch helper and Engine.gitPushIfConfigured method

Motivation

During long-running autonomous pipeline executions (e.g., feature factories that loop for hours), all committed work lives only on the local run branch until the user manually pushes. If the machine dies, hours of work are lost. This change ensures completed work is pushed to a remote after each successful loop iteration.

Usage

git:
  push_remote: origin  # optional; omit to disable auto-push

Test plan

• TestGitPushIfConfigured_NoPushRemote - no-op when push_remote is empty
• TestGitPushIfConfigured_NilRunConfig - no-op when config is nil
• TestGitPushIfConfigured_NilEngine - no-op on nil receiver
• TestGitPushIfConfigured_PushesToRemote - verifies branch appears on bare remote
• TestLoopRestart_PushesOnRestart - full integration: loop_restart triggers push to bare remote
• go vet clean
• go build ./... clean

🤖 Generated with Claude Code

[danshapiro]

🎉 This is fantastic work! The best-effort push design is exactly right — protecting long-running autonomous runs from data loss without ever risking an abort on push failure is a really elegant approach.

The defensive nil checks, the clean progress event lifecycle (git_push_start → git_push_ok/git_push_failed), and the thorough test coverage (including the full loop_restart integration test) are all top-notch.

I added a small hardening commit on top:

• 2-minute timeout on git push via exec.CommandContext so a network stall or stuck credential prompt can't hang the run
• GIT_TERMINAL_PROMPT=0 to prevent interactive auth prompts from blocking
• Documented push_remote in kilroy-metaspec.md so the schema stays in sync

All tests passing. Merged — great contribution! 🚀

— Codex