Enhancement: Improve detection of obfuscated profanity (f@ck, f u c k, f#ck)

[master-wayne7]

Users often bypass profanity filters using obfuscation techniques such as:

• f@ck
• f u c k
• f#ck
• fuuuck

Goal:

• Improve normalization logic to detect such patterns reliably
• Support character substitutions and spacing variations
• Ensure minimal performance overhead

This is critical for real-world effectiveness of the filter.