fix(macos-container): set host terminal to raw mode for container exec

Apple's container exec --interactive --tty does not put the host
terminal into raw mode before starting its I/O relay.  In cooked
(canonical) mode the kernel line discipline buffers modifier-key
escape sequences — e.g. Shift+Enter in modifyOtherKeys mode generates
\x1b[13;2~ — until a carriage-return arrives, so they never reach
Claude Code inside the container.

Add pty_forward.py, a stdlib-only wrapper (modelled on the existing
smolmachines pty_resize.py) that sets the host terminal to raw mode
via tty.setraw(), spawns the container exec command, and restores the
original terminal attributes on exit.  Falls back to a bare
subprocess.run when stdin is not a TTY (piped invocations, CI) or
when termios operations fail.

Also retain the --env TERM=<host> forwarding from the previous commit:
without TERM inside the container session, Claude Code cannot determine
which modifier-key protocol to enable even with raw mode correctly set.

Non-TTY exec paths (bottle.exec, cp_in) are unaffected.

tests/unit/test_macos_container_pty_forward.py

@@ -0,0 +1,136 @@
+"""Unit: macos-container pty_forward raw-mode wrapper (issue #245).
+
+Tests argument parsing, non-TTY fallback, and the raw-mode
+setup/restore sequence without requiring a real terminal.
+"""
+
+from __future__ import annotations
+
+import io
+import termios
+import unittest
+from unittest.mock import MagicMock, patch
+
+from bot_bottle.backend.macos_container import pty_forward
+
+
+def _fake_stdin(fd: int = 0) -> MagicMock:
+    """Return a mock stdin whose fileno() returns *fd*."""
+    m = MagicMock()
+    m.fileno.return_value = fd
+    return m
+
+
+class TestArgvParsing(unittest.TestCase):
+    def test_missing_separator_returns_error_exit_code(self):
+        with patch.object(pty_forward.sys, "stderr", new=io.StringIO()) as err:
+            rc = pty_forward.main(["container", "exec"])
+        self.assertEqual(2, rc)
+        self.assertIn("usage:", err.getvalue())
+
+    def test_too_few_args_returns_error_exit_code(self):
+        with patch.object(pty_forward.sys, "stderr", new=io.StringIO()):
+            self.assertEqual(2, pty_forward.main([]))
+            self.assertEqual(2, pty_forward.main(["--"]))
+
+    def test_separator_at_start_with_inner_is_valid(self):
+        with (
+            patch.object(pty_forward.sys, "stdin", _fake_stdin()),
+            patch.object(pty_forward.os, "isatty", return_value=False),
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 0
+            rc = pty_forward.main(["--", "container", "exec"])
+        self.assertEqual(0, rc)
+        run.assert_called_once_with(["container", "exec"], check=False)
+
+
+class TestNonTtyFallback(unittest.TestCase):
+    def test_non_tty_stdin_runs_inner_directly(self):
+        with (
+            patch.object(pty_forward.sys, "stdin", _fake_stdin()),
+            patch.object(pty_forward.os, "isatty", return_value=False),
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 42
+            rc = pty_forward.main(
+                ["--", "container", "exec", "--interactive", "--tty", "c", "claude"]
+            )
+        self.assertEqual(42, rc)
+        run.assert_called_once_with(
+            ["container", "exec", "--interactive", "--tty", "c", "claude"],
+            check=False,
+        )
+
+    def test_fileno_error_runs_inner_directly(self):
+        bad_stdin = MagicMock()
+        bad_stdin.fileno.side_effect = OSError("pseudofile")
+        with (
+            patch.object(pty_forward.sys, "stdin", bad_stdin),
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 0
+            rc = pty_forward.main(["--", "container", "exec"])
+        run.assert_called_once_with(["container", "exec"], check=False)
+        self.assertEqual(0, rc)
+
+
+class TestRawModeSetupAndRestore(unittest.TestCase):
+    def test_tty_stdin_sets_raw_mode_and_restores_on_exit(self):
+        saved_attrs = object()
+        with (
+            patch.object(pty_forward.sys, "stdin", _fake_stdin()),
+            patch.object(pty_forward.os, "isatty", return_value=True),
+            patch.object(pty_forward.termios, "tcgetattr", return_value=saved_attrs),
+            patch.object(pty_forward.tty, "setraw") as setraw,
+            patch.object(pty_forward.termios, "tcsetattr") as tcsetattr,
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 0
+            rc = pty_forward.main(["--", "container", "exec"])
+
+        self.assertEqual(0, rc)
+        setraw.assert_called_once()
+        tcsetattr.assert_called_once_with(
+            unittest.mock.ANY, termios.TCSADRAIN, saved_attrs,
+        )
+
+    def test_tty_restores_on_subprocess_nonzero_exit(self):
+        saved_attrs = object()
+        with (
+            patch.object(pty_forward.sys, "stdin", _fake_stdin()),
+            patch.object(pty_forward.os, "isatty", return_value=True),
+            patch.object(pty_forward.termios, "tcgetattr", return_value=saved_attrs),
+            patch.object(pty_forward.tty, "setraw"),
+            patch.object(pty_forward.termios, "tcsetattr") as tcsetattr,
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 1
+            rc = pty_forward.main(["--", "container", "exec"])
+
+        self.assertEqual(1, rc)
+        tcsetattr.assert_called_once_with(
+            unittest.mock.ANY, termios.TCSADRAIN, saved_attrs,
+        )
+
+    def test_tcgetattr_error_falls_back_to_bare_run(self):
+        with (
+            patch.object(pty_forward.sys, "stdin", _fake_stdin()),
+            patch.object(pty_forward.os, "isatty", return_value=True),
+            patch.object(
+                pty_forward.termios, "tcgetattr",
+                side_effect=termios.error("not a tty"),
+            ),
+            patch.object(pty_forward.tty, "setraw") as setraw,
+            patch.object(pty_forward.subprocess, "run") as run,
+        ):
+            run.return_value.returncode = 0
+            rc = pty_forward.main(["--", "container", "exec"])
+
+        setraw.assert_not_called()
+        run.assert_called_once_with(["container", "exec"], check=False)
+        self.assertEqual(0, rc)
+
+
+if __name__ == "__main__":
+    unittest.main()