fix(git): refuse duplicate values, show list errors, Escape on Add

Review findings. With a key holding the same value twice, --fixed-value
--replace-all rewrote both and merged two rows into one, and --unset
failed on both; gitcfg now counts the matches and refuses anything but
exactly one, pointing at the editor. A file git cannot parse made list
print nothing, which the page drew as an empty config; list now prints
git's error as an error= line and the page shows it. Escape in the Add
fields clears the typed text before it leaves the page, as a row's edit
is undone first.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions