```python
def check_manifest(line: dict) -> dict:
    if not line:
        return {}

    sku = line.get('sku', '').strip().upper()
    if not sku:
        return {}

    count = line.get('count', 0)
    if not isinstance(count, int) or count <= 0:
        return {}

    note = line.get('note', '')
    if not isinstance(note, str):
        return {}

    return {key: value for key, value in line.items() if key in ['sku', 'count', 'note']}
```