fix(node): make init, node.toml editing and CLI output work on Windows

Found by running the daemon on Windows for the first time:

- `meshbay-node init` wrote `unlock_file = "C:\Users\..."`, and
  attach_group / add_root write `path = "C:\..."` — a raw Windows path in a
  TOML basic string is a parse error (`\U`, `\a`, ... are escape sequences),
  so the config would not load. All now write `Path(...).as_posix()`;
  pathlib reads the forward-slash form fine on Windows.
- any `print()` carrying a `->` arrow or em dash (the CLI help and messages
  are full of them) raised UnicodeEncodeError on a cp1252 console and took
  the command down. New `platform.force_utf8_stdio()` reconfigures
  stdout/stderr to UTF-8, called at the top of `main()`.

Verified on Windows: init writes parseable LF node.toml, the keystore
Argon2-decrypts, the loopback control API binds 127.0.0.1, and
`_update_node_toml` reads a CRLF file and rewrites it LF-only with its
standalone comments intact. Two regression tests added in test_ops.py.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

4 files changed, 68 insertions, 7 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/daemon.py b/packages/meshbay-node/src/meshbay_node/daemon.py
index 72f7fa4..6bc3bef 100644
--- a/packages/meshbay-node/src/meshbay_node/daemon.py
+++ b/packages/meshbay-node/src/meshbay_node/daemon.py
@@ -1634,7 +1634,8 @@ def _systemctl_user(verb: str, unit: str, *, not_running_hint: str,
 def main() -> None:
     import argparse
 
-    from meshbay_node.platform import use_compatible_event_loop
+    from meshbay_node.platform import force_utf8_stdio, use_compatible_event_loop
+    force_utf8_stdio()
     use_compatible_event_loop()
 
     parser = argparse.ArgumentParser(description="MeshBay Node daemon")
@@ -1738,7 +1739,9 @@ def main() -> None:
                 "ui_port   = 18000",
                 "",
                 "[keystore]",
-                f'unlock_file = "{unlock_file}"',
+                # Forward slashes: a Windows path in a TOML basic string is a
+                # parse error (`\U`, `\a`, ... are escape sequences).
+                f'unlock_file = "{unlock_file.as_posix()}"',
                 "",
             ]
             cfg_path.write_text("\n".join(toml_lines) + "\n", encoding="utf-8", newline="\n")
diff --git a/packages/meshbay-node/src/meshbay_node/ops.py b/packages/meshbay-node/src/meshbay_node/ops.py
index 40de755..4c20c2a 100644
--- a/packages/meshbay-node/src/meshbay_node/ops.py
+++ b/packages/meshbay-node/src/meshbay_node/ops.py
@@ -447,9 +447,11 @@ async def attach_group(state: dict, name: str, shared_dir: str,
                 upload_path.mkdir(parents=True, exist_ok=True)
             except OSError as e:
                 raise OpError(f"Cannot create {upload_path}: {e}") from e
-            block += f'upload_dir  = "{upload_path}"\n'
+            block += f'upload_dir  = "{upload_path.as_posix()}"\n'
     block += (f'\n  [[groups.roots]]\n'
-              f'  path   = "{path}"\n')
+              # Forward slashes: a Windows path in a TOML basic string is a
+              # parse error (`\U`, `\a`, ... are escapes). pathlib reads `/`.
+              f'  path   = "{path.as_posix()}"\n')
     if not separate_upload:
         block += f'  upload = true\n'
     try:
@@ -667,7 +669,7 @@ async def add_root(state: dict, group_id: str, path: str, *,
         raise OpError(f"Cannot create {added.path}: {e}") from e
 
     conf_path = Path(state.get("config_path") or DEFAULT_CONFIG_PATH)
-    root_block = f'  [[groups.roots]]\n  path   = "{added.path}"'
+    root_block = f'  [[groups.roots]]\n  path   = "{added.path.as_posix()}"'
     if name:
         root_block += f'\n  name   = "{added.name}"'
     if kind != "generic":
diff --git a/packages/meshbay-node/src/meshbay_node/platform.py b/packages/meshbay-node/src/meshbay_node/platform.py
index 4bd8e35..80aa6ae 100644
--- a/packages/meshbay-node/src/meshbay_node/platform.py
+++ b/packages/meshbay-node/src/meshbay_node/platform.py
@@ -6,6 +6,24 @@ import shutil
 import sys
 from pathlib import Path
 
+# ── Console ──────────────────────────────────────────────────────────────────
+
+
+def force_utf8_stdio() -> None:
+    """
+    Make stdout/stderr UTF-8. A Windows console is cp1252 by default, so any
+    ``print()`` carrying a character outside it — the ``->`` arrows and em
+    dashes the CLI help and messages are full of — raises UnicodeEncodeError
+    and takes the command down with it. No effect where the streams are
+    already UTF-8 or cannot be reconfigured.
+    """
+    for stream in (sys.stdout, sys.stderr):
+        try:
+            stream.reconfigure(encoding="utf-8")
+        except (AttributeError, ValueError, OSError):
+            pass
+
+
 # ── Event loop ───────────────────────────────────────────────────────────────
 
 
diff --git a/packages/meshbay-node/tests/test_ops.py b/packages/meshbay-node/tests/test_ops.py
index 83758ae..92e32bf 100644
--- a/packages/meshbay-node/tests/test_ops.py
+++ b/packages/meshbay-node/tests/test_ops.py
@@ -15,12 +15,11 @@ from pathlib import Path
 
 import pytest
 from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
-
-from conftest import one_root
 from meshbay_node import ops
 from meshbay_node.indexer.group_index import GroupIndex
 from meshbay_node.transport.quic_server import Denylist
 
+from conftest import one_root
 
 
 def _state(tmp_path: Path) -> dict:
@@ -251,3 +250,42 @@ async def test_start_reload_without_fn_is_refused(tmp_path):
     state = _state(tmp_path)
     with pytest.raises(ops.OpError, match="Reload not available"):
         await ops.start_reload(state)
+
+
+# ── node.toml editing survives Windows (LF, comments, backslash paths) ────────
+
+def test_update_node_toml_forces_lf_and_keeps_standalone_comments(tmp_path):
+    p = tmp_path / "node.toml"
+    p.write_bytes("\r\n".join([
+        "[hub]", 'url = "http://x"', "",
+        "[node]",
+        "# how long an invitation lives",
+        "invite_ttl_hours = 168",
+        "ui_port = 18000",
+        "",
+        "[[groups]]", 'id = "g1"',
+    ]).encode())
+
+    ops._update_node_toml(p, {"invite_ttl_hours": 24, "max_concurrent_streams": 4})
+
+    raw = p.read_bytes()
+    assert b"\r\n" not in raw, "must be rewritten LF-only, whatever it was read as"
+    text = raw.decode("utf-8")
+    assert "# how long an invitation lives" in text
+    import tomllib
+    node = tomllib.loads(text)["node"]
+    assert node["invite_ttl_hours"] == 24
+    assert node["max_concurrent_streams"] == 4
+
+
+def test_a_backslash_path_written_into_node_toml_stays_parseable():
+    # attach_group / add_root / init embed a directory into a TOML basic string.
+    # A raw Windows path there (drive + backslash + "Users" + ...) is a parse
+    # error since backslash sequences are escapes; the code writes as_posix().
+    import tomllib
+    bs = chr(92)
+    win_dir = f"C:{bs}Users{bs}alice{bs}Media"
+    assert tomllib.loads(f'path = "{Path(win_dir).as_posix()}"\n')["path"] == \
+        "C:/Users/alice/Media"
+    with pytest.raises(tomllib.TOMLDecodeError):
+        tomllib.loads(f'path = "{win_dir}"\n')   # the bug this guards against