ExecContext: Map ENOTDIR to FileNotFoundError

_raise_stat_error() maps the message of a failed remote stat to an
exception. A stat below a file answers "not a directory", which falls
through to the generic EIO: the path is simply absent, and callers see a
re-raised error instead of the FileNotFoundError the "no such file" branch
already gives. Map it to FileNotFoundError, so existence checks see
absence.

Assisted-by: unsloth/Qwen3.8-27B-GGUF:Q4_K_M with pi.dev v0.99.2
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ExecContext.py

@@ -37,6 +37,8 @@ def _raise_stat_error(path: str, result: Result) -> None:
     lower = msg.lower()
     if 'no such file' in lower:
         raise FileNotFoundError(errno.ENOENT, msg, path)
+    if 'not a directory' in lower:
+        raise FileNotFoundError(errno.ENOTDIR, msg, path)
     if 'permission denied' in lower or 'operation not permitted' in lower:
         raise PermissionError(errno.EACCES, msg, path)
     raise OSError(errno.EIO, msg, path)