auto make shebang files executable

etc--supervisor.d--fswatch-chmod.ini

[program:fswatch-chmod]
# For each changed file:
# - skips if not regular file
# - skips if no shebang
# - finds enclosing git repo (if any)
# - skips if file tracked and unchanged in that repo (prevent mangling checkouts / rebases)
# - otherwise makes file executable
# - ignore files inside .git but allow in .git/hooks/
command=bash -c '
    /opt/homebrew/bin/fswatch -v -r ~/bin ~/src --exclude /\.git/ --include /\.git/hooks/ |
    while read file; do
      [[ -f "$file" ]]                 || continue                               # skip unless is regular file
      head -n1 "$file" | grep -q "^#!" || continue                               # skip unless is shebang
      repo=$(git -C "$(dirname "$file")" rev-parse --show-toplevel 2>/dev/null)  # repo root
      rel="${file#$repo/}"                                                       # relative path within repo
      [[ -n "$repo" ]] &&                                                        # is repo
        git -C "$repo" ls-files --error-unmatch "$rel" &>/dev/null &&            # is tracked
        git -C "$repo" diff --quiet -- "$rel" &>/dev/null &&                     # is unchanged
        continue                                                                 # skip if in git and tracked and unchanged
      chmod +x "$file"
    done'
user=kch
autostart=true
autorestart=true
redirect_stderr=true
stdout_logfile=/tmp/fswatch-chmod.log
numprocs=1
stopasgroup=true        # Kills whole process group
killasgroup=true        # Ensures child processes are killed
startsecs=2             # Wait to ensure stable start