QMK CLI Environment bootstrapper (#25038)

Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: Pascal Getreuer <getreuer@google.com>

lib/python/qmk/keyboard.py

@@ -175,8 +175,9 @@ def keyboard_completer(prefix, action, parser, parsed_args):
     return list_keyboards()
 
 
+@lru_cache(maxsize=None)
 def list_keyboards():
-    """Returns a list of all keyboards
+    """Returns a list of all keyboards.
     """
     # We avoid pathlib here because this is performance critical code.
     kb_wildcard = os.path.join(base_path, "**", 'keyboard.json')
@@ -184,6 +185,9 @@ def list_keyboards():
 
     found = map(_find_name, paths)
 
+    # Convert to posix paths for consistency
+    found = map(lambda x: str(Path(x).as_posix()), found)
+
     return sorted(set(found))