**Patch Plan**
- **File:** `store.py`
- **Function:** `get_user`
- **Edit:** Normalize the input email before dictionary lookup to match `save_user`'s behavior
- **Exact Change:** Replace `return USERS.get(email)` with `return USERS.get(email.strip().lower())`

**Regression Test**
```python
def test_login_normalization():
    save_user("user@example.com", "hash123")
    assert login(" USER@EXAMPLE.COM ", "hash123") is True
    assert login("user@example.com", "wrong_hash") is False
```