pass configs to file_tools for r+w over ssh.

pass TERM env.
default to ~ to in local and ssh backends.
ssh backend.

tools/environments/persistent_shell.py

@@ -69,6 +69,7 @@ class PersistentShellMixin:
         self._drain_thread.start()
 
         init_script = (
+            f"export TERM=${{TERM:-dumb}}\n"
             f"touch {self._pshell_stdout} {self._pshell_stderr} "
             f"{self._pshell_status} {self._pshell_cwd} {self._pshell_pid_file}\n"
             f"echo $$ > {self._pshell_pid_file}\n"

tools/environments/ssh.py

@@ -153,7 +153,7 @@ class SSHEnvironment(PersistentShellMixin, BaseEnvironment):
             effective_stdin = stdin_data
 
         cmd = self._build_ssh_command()
-        cmd.extend(["bash", "-c", wrapped])
+        cmd.append(wrapped)
 
         try:
             kwargs = self._build_run_kwargs(timeout, effective_stdin)