Add ColorNote color index filter

.gitignore

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+*.backup
+*.jex
+*.json
+

exclude_by_color_index.py

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+#!/usr/bin/env python3
+import argparse
+import json
+from pathlib import Path
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description="Copy a ColorNote JSON export while excluding notes by color_index."
+    )
+    parser.add_argument(
+        "input_file",
+        type=Path,
+        help="Source JSON file produced by the ColorNote decrypt script.",
+    )
+    parser.add_argument(
+        "output_file",
+        type=Path,
+        help="Destination JSON file.",
+    )
+    parser.add_argument(
+        "--exclude-color-index",
+        type=int,
+        required=True,
+        help="color_index value to exclude from the copied JSON.",
+    )
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+    notes = json.loads(args.input_file.read_text(encoding="utf-8-sig"))
+
+    kept = [
+        note for note in notes
+        if note.get("color_index") != args.exclude_color_index
+    ]
+
+    args.output_file.write_text(
+        json.dumps(kept, ensure_ascii=False, indent=2),
+        encoding="utf-8-sig",
+    )
+
+    removed = len(notes) - len(kept)
+    print(f"Input records: {len(notes)}")
+    print(f"Removed color_index={args.exclude_color_index}: {removed}")
+    print(f"Output records: {len(kept)}")
+    print(f"Wrote: {args.output_file}")
+
+
+if __name__ == "__main__":
+    main()