docs: Clarify default encoding behavior in documentation (#2693)

* docs: Clarify default encoding behavior and cross-platform considerations

* docs: update CLI reference documentation

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Author: koxudaxi

docs/cli-reference/base-options.md

@@ -19,7 +19,9 @@ Specify character encoding for input and output files.
 The `--encoding` flag sets the character encoding used when reading
 the schema file and writing the generated Python code. This is useful
 for schemas containing non-ASCII characters (e.g., Japanese, Chinese).
-Default is utf-8.
+Default is the system's preferred encoding (via `locale.getpreferredencoding()`),
+which is typically UTF-8 on Linux/macOS but may differ on Windows (e.g., cp1252).
+For consistent cross-platform behavior, explicitly specify `--encoding utf-8`.
 
 !!! tip "Usage"
 

tests/test_main_kr.py

@@ -1284,7 +1284,9 @@ def test_encoding_option(output_file: Path) -> None:
     The `--encoding` flag sets the character encoding used when reading
     the schema file and writing the generated Python code. This is useful
     for schemas containing non-ASCII characters (e.g., Japanese, Chinese).
-    Default is utf-8.
+    Default is the system's preferred encoding (via `locale.getpreferredencoding()`),
+    which is typically UTF-8 on Linux/macOS but may differ on Windows (e.g., cp1252).
+    For consistent cross-platform behavior, explicitly specify `--encoding utf-8`.
     """
     run_main_and_assert(
         input_path=JSON_SCHEMA_DATA_PATH / "encoding_test.json",