Term Coder v1.28.3

Fixes the branch selector under the composer, which always reported "Not a git repository (or git unavailable)" even inside a healthy repo.

Root cause — the branch list ran through the app's login-shell wrapper as zsh -lic "git for-each-ref --format=%(refname:short) refs/heads". Those wrapper double quotes are consumed before zsh parses the line, so zsh saw the bare %(refname:short) and aborted with zsh:1: missing end of string (exit 1) on every repo. git branch --show-current contains no parens and worked, which masked the real failure as 'not a git repository'.

Fix — the --format value is now single-quoted inside the command (--format='%(refname:short)'), so it survives every shell layer. Verified by replaying the exact wrapper against a real repo: exit 1 → exit 0 with the full branch list. Regression test added; full suite (26 files) passes.