test(node): make the suite pass on Windows

- `.read_text()` on source files now `encoding="utf-8"` — cp1252 chokes on
  the em dashes / box-drawing chars those files contain.
- test node.toml templates embed paths via `Path.as_posix()`: a raw Windows
  path in a basic TOML string is a parse error (`\U`, `\a`, ... are escapes).
- new `test_platform.py` covers `meshbay_node.platform` by mocking
  `sys.platform` / `os.environ` — runs on both OSes.
- `skipif(sys.platform == "win32")`, in `conftest.needs_subprocess` and
  inline, for the documented gaps: ffmpeg/ffprobe via asyncio subprocess
  (the win32 selector loop, forced for aiortc, cannot spawn one), the
  systemd `reload`/`restart-daemon` delegation (Windows path is W3), the
  keystore `st_mode == 600` assertion (NTFS ignores mode bits), and the
  symlink-escape test (needs Developer Mode).

Windows: 781 passed, 25 skipped. No change on Linux.

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

1 files changed, 8 insertions, 1 deletions

diff --git a/packages/meshbay-node/tests/test_enrich.py b/packages/meshbay-node/tests/test_enrich.py
index a35c713..75cf0ee 100644
--- a/packages/meshbay-node/tests/test_enrich.py
+++ b/packages/meshbay-node/tests/test_enrich.py
@@ -5,6 +5,8 @@ import shutil
 import subprocess
 from pathlib import Path
 
+import sys
+
 import pytest
 
 from meshbay_common.protocol import IndexEntry
@@ -131,7 +133,12 @@ def test_synthetic_episode_number_does_not_collide_across_per_season_bonus_folde
 
 # ── end-to-end against a real (tiny, synthetic) video file ──────────────────
 
-pytestmark_ffmpeg = pytest.mark.skipif(not _HAVE_FFMPEG, reason="ffmpeg/ffprobe not installed")
+# ffprobe runs via asyncio subprocess, which the win32 selector loop (forced
+# for aiortc, see devel/windows-devel.md §5) cannot spawn.
+pytestmark_ffmpeg = pytest.mark.skipif(
+    not _HAVE_FFMPEG or sys.platform == "win32",
+    reason="needs ffprobe installed and a ProactorEventLoop",
+)
 
 
 def _make_clip(path: Path) -> None: