feat: v0.5.5 - enhanced priority fee system and dependency updates

- Update solana-streamer-sdk to 0.4.1
- Refactor priority fee API (custom_buy_tip_fee → custom_priority_fee)
- Simplify documentation and clean up examples

BREAKING CHANGE: priority fee parameter type changed

examples/pumpfun_copy_trading/src/main.rs

@@ -146,7 +146,6 @@ async fn pumpfun_copy_trade_with_grpc(trade_info: PumpFunTradeEvent) -> AnyResul
             Box::new(PumpFunParams::from_trade(&trade_info, None)),
             None,
             true,
-            None,
         )
         .await?;
 
@@ -173,7 +172,6 @@ async fn pumpfun_copy_trade_with_grpc(trade_info: PumpFunTradeEvent) -> AnyResul
             Box::new(PumpFunParams::from_trade(&trade_info, Some(true))),
             None,
             true,
-            None,
         )
         .await?;