Function parse_faillock_config 

pub fn parse_faillock_config() -> Result<FaillockConfig, String>

What: Parse faillock configuration from /etc/security/faillock.conf.

Inputs: None (reads from system config file).

Output:

• Ok(FaillockConfig) with parsed values, or Err(String) on error.

Errors

• Returns Err if the config file cannot be read (though defaults are used in practice).

Details:

• Reads /etc/security/faillock.conf.
• Parses deny setting (default 3 if commented out).
• Parses fail_interval setting (default 15 minutes if commented out).
• Handles comments (lines starting with #) and whitespace.