Four copies of the same loop ran `git remote` and then a serial
`git remote get-url <name>` per remote to answer "which remote has this
URL". On a repo with 58 remotes that is 59 subprocesses -- measured at
1083 ms -- for one question, and worktree create asks it several times.
`git remote -v` answers for every remote from one child, reporting the
same insteadOf-expanded first fetch URL `get-url` prints.
The batched `cat-file --batch-check` branch-conflict probe decides from
stdout, but its WSL route was unfenced, so a login-shell fallback printed
the distro banner onto the stream it parses. That broke the
one-line-per-ref contract, made every batch undecided, and fell straight
back to one `show-ref` per remote -- the cost the batch exists to remove.
Measured at 58 remotes / 4346 branches, spawns and wall time:
push-target remote scan 59 -> 1 (1083 ms -> 8 ms)
branch-conflict probe 60 -> 3 (984 ms -> 43 ms)
configured push target 123 -> 6 (2707 ms -> 157 ms)
