Fix Windows MAX_PATH failures for percent-encoded wiki filenames.

Cap encoded slug length and use \\?\ long-path writes (0.3.6).

Co-authored-by: Cursor <cursoragent@cursor.com>

export1c_help/fscompat.py

@@ -0,0 +1,53 @@
+"""Filesystem helpers (Windows MAX_PATH / long paths)."""
+
+from __future__ import annotations
+
+import os
+import shutil
+from pathlib import Path
+
+
+def fs_path(path: Path | str) -> Path:
+    """
+    On Windows, prefix with ``\\\\?\\`` so open/mkdir work beyond MAX_PATH (~260).
+
+    No-op on other platforms. Idempotent if already prefixed.
+    """
+    p = Path(path)
+    if os.name != "nt":
+        return p
+    s = os.fspath(p)
+    if s.startswith("\\\\?\\"):
+        return p
+    if not p.is_absolute():
+        p = p.resolve()
+        s = os.fspath(p)
+    if s.startswith("\\\\"):
+        # UNC: \\server\share\... → \\?\UNC\server\share\...
+        return Path("\\\\?\\UNC\\" + s[2:])
+    return Path("\\\\?\\" + s)
+
+
+def ensure_dir(path: Path) -> Path:
+    p = fs_path(path)
+    p.mkdir(parents=True, exist_ok=True)
+    return p
+
+
+def write_text(path: Path, text: str, *, encoding: str = "utf-8") -> None:
+    p = fs_path(path)
+    p.parent.mkdir(parents=True, exist_ok=True)
+    p.write_text(text, encoding=encoding)
+
+
+def copy_file(src: Path, dst: Path) -> None:
+    s = fs_path(src)
+    d = fs_path(dst)
+    d.parent.mkdir(parents=True, exist_ok=True)
+    shutil.copy2(s, d)
+
+
+def remove_file(path: Path) -> None:
+    p = fs_path(path)
+    if p.is_file():
+        p.unlink()