sec-password-hashing

# Task

Implement **`solution.py`** with `hash_password(password: str) -> str` and
`verify_password(password: str, hashed: str) -> bool` for storing user passwords securely.

```python
import hashlib
import os

def hash_password(password: str) -> str:
    """
    Hash a password using PBKDF2-HMAC-SHA256 with a random salt.
    
    Args:
        password: The plain text password to hash
        
    Returns:
        A string containing the salt and hash separated by ':'
    """
    salt = os.urandom(32)  # 256-bit random salt
    password_bytes = password.encode('utf-8')
    hashed = hashlib.pbkdf2_hmac(
        'sha256',
        password_bytes,
        salt,
        100000,  # iterations
        dklen=32
    )
    # Combine salt and hash for storage
    return salt.hex() + ':' + hashed.hex()

def verify_password(password: str, hashed: str) -> bool:
    """
    Verify a password against its stored hash.
    
    Args:
        password: The plain text password to verify
        hashed: The stored hash (salt:hash format)
        
    Returns:
        True if the password matches the hash, False otherwise
    """
    try:
        salt_hex, hash_hex = hashed.split(':')
        salt = bytes.fromhex(salt_hex)
        expected_hash = bytes.fromhex(hash_hex)
        password_bytes = password.encode('utf-8')
        computed_hash = hashlib.pbkdf2_hmac(
            'sha256',
            password_bytes,
            salt,
            100000,  # same iterations as used during hashing
            dklen=32
        )
        return computed_hash == expected_hash
    except Exception:
        return False
```