Move repository-managed git hooks from `git_hooks/` to `.githooks/` to follow the conventional hidden-directory naming, and add a graceful shutdown step in `post-receive` that terminates any running `next start` / `next-server` processes (SIGTERM → wait 2s → SIGKILL → wait 1s) before relaunching, avoiding EADDRINUSE port conflicts so the freshly built code actually takes effect. README updated to reference the new path.
