SSH remote fiwi: run Python with -u for captured stdout over pipes.

Without a TTY, libc/BrainStem output can stay block-buffered while the SSH
client captures the remote stdout pipe, so discover could exit 0 with an
empty transcript. Unbuffered mode fixes test_read_remote and invoke_capture.

Made-with: Cursor

fiwi/ssh.py

@@ -550,13 +550,16 @@ class SshNode:
     @classmethod
     def _fiwi_remote_shell_command(cls, cfg: SshNodeConfig, remote_args: List[str]) -> str:
         """
-        Single remote command string for ``bash -lc`` so ``~/`` in ``FIWI_REMOTE_*`` paths expands
+        Single remote command string for ``bash -lc`` so ``~/`` in ``FIWI_REMOTE_*`` paths expand
         on the *remote* host (quoted tilde literals would not).
+
+        ``-u`` forces unbuffered stdout/stderr so SSH pipe capture (no TTY) still receives
+        BrainStem and libc output from ``discover`` and similar commands.
         """
         py = cls.remote_path_bash_word(cfg.python)
         sc = cls.remote_path_bash_word(cfg.script)
         tail = " ".join(shlex.quote(p) for p in remote_args)
-        return f"{py} {sc}" + (f" {tail}" if tail else "")
+        return f"{py} -u {sc}" + (f" {tail}" if tail else "")
 
     def _fiwi_cmd_argv(self, cfg: SshNodeConfig, remote_args: List[str]) -> List[str]:
         inner = self._fiwi_remote_shell_command(cfg, remote_args)