test(#91): assert sidecar paths via as_posix() for the Windows CI runner

The CI matrix includes a windows-latest job where str(Path("/Users/…")) renders
with backslashes, so the platform-parameterised sidecar-path assertions failed
there (macOS/Linux passed). Compare .as_posix() instead — separator-normalised
and portable — and note why. Pure test fix; no production-code change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_core.py

@@ -3305,20 +3305,23 @@ _HOME = "/Users/tester"
 
 
 def test_sidecar_path_verified_per_platform():
+    # NOTE: assert on .as_posix() — the CI matrix includes a Windows runner where
+    # str(Path("/Users/…")) would render with backslashes. as_posix() normalises
+    # separators so these platform-parameterised checks are portable.
     spec = c.SERVER_SPECS["ssh-mcp"]
     mac = c.sidecar_path(spec, platform="darwin", environ={}, home=_HOME)
-    assert str(mac) == "/Users/tester/Library/Application Support/ssh-mcp/config.toml"
+    assert mac.as_posix() == "/Users/tester/Library/Application Support/ssh-mcp/config.toml"
     # Windows resolves under %APPDATA%, not ~/.config.
     win = c.sidecar_path(
         spec, platform="win32", environ={"APPDATA": "C:/Users/t/AppData/Roaming"}, home=_HOME
     )
-    assert "ssh-mcp/config.toml" in str(win)
-    assert "AppData/Roaming" in str(win)
+    assert "ssh-mcp/config.toml" in win.as_posix()
+    assert "AppData/Roaming" in win.as_posix()
     # POSIX honours XDG_CONFIG_HOME, else ~/.config.
     xdg = c.sidecar_path(spec, platform="linux", environ={"XDG_CONFIG_HOME": "/cfg"}, home=_HOME)
-    assert str(xdg) == "/cfg/ssh-mcp/config.toml"
+    assert xdg.as_posix() == "/cfg/ssh-mcp/config.toml"
     default = c.sidecar_path(spec, platform="linux", environ={}, home=_HOME)
-    assert str(default) == "/Users/tester/.config/ssh-mcp/config.toml"
+    assert default.as_posix() == "/Users/tester/.config/ssh-mcp/config.toml"
 
 
 def test_sidecar_path_none_for_non_sidecar_package():
@@ -3355,7 +3358,7 @@ def test_sidecar_args_live_when_file_absent():
 def test_sidecar_wrong_path_flag_on_macos():
     # A TOML written at the README's ~/.config path is never read on macOS.
     doc = c.sidecar_doc_path(c.SERVER_SPECS["ssh-mcp"], home=_HOME)
-    assert str(doc) == "/Users/tester/.config/ssh-mcp/config.toml"
+    assert doc.as_posix() == "/Users/tester/.config/ssh-mcp/config.toml"
     st = c.sidecar_status(
         _SSH, platform="darwin", environ={}, home=_HOME, exists=lambda p: p == doc
     )