feat: Implement dynamic fee logic scaffolding based on pool volatility

[AlAfiz]

Description

A static 0.3% fee is great, but next-generation DEXs adjust their fees dynamically based on market volatility.
If a pool is experiencing massive, unbalanced trades, the fee should temporarily increase to protect Liquidity Providers from impermanent loss.
We need to scaffold a function that calculates a "Volatility Multiplier" based on the ratio of recent trade sizes to total reserves.
For now, we will document the logic and return a mock multiplier so the core swap math can integrate it later.

Requirements

• Create a helper function calculate_volatility_fee_multiplier(trade_size, pool_reserve).
• If the trade size is less than 1% of the reserve, return a multiplier of 1.0 (standard 0.3% fee).
• If the trade size exceeds 5% of the reserve, return a multiplier of 1.5 (effectively a 0.45% fee).
• Add detailed inline documentation explaining how this protects LPs during extreme market events.