[zerone0x]

Summary

• Fixes [Bug]: git returned error "the receiving end does not support push options" when creating an environment #323: git push to the local bare repository fails with fatal: the receiving end does not support push options when the user's git config has push.pushOption set or when using newer git versions that send push options by default.
• Sets receive.advertisePushOptions=true on the bare fork repo during initialization so it accepts push options.
• Adds a test assertion to verify the config is set correctly.

Test plan

• Existing TestRepositoryOpen/valid_git_repository test passes and now also verifies receive.advertisePushOptions is set
• go test -short ./... passes (pre-existing failures in TestSelectiveFileStaging are unrelated)

[awdemos]

Endorsed for merge.

• Enables receive.advertisePushOptions on the local bare fork repo, fixing pushes when the user repo has push options configured (issue [Bug]: git returned error "the receiving end does not support push options" when creating an environment #323).
• Includes a regression test verifying the config is set.
• Verified: go test -short ./repository/... passes.

[awdemos]

@zerone0x friendly ping — this PR currently has merge conflicts with . Could you rebase onto and resolve the conflicts? Once clean I'll re-endorse.

[zerone0x]

Rebased onto 2e43e62, conflicts in repository/repository.go resolved; go build ./... and go test -short ./repository/... pass. New head: 2dfe156.

Upstream ensureFork now also handles fork repos that already exist (#362). Because of that, receive.advertisePushOptions=true is now set on every ensureFork call, right after setupConfigInclude, so forks created before this fix get it too. The fork dir is only removed on failure when it was just created.