refactor: restructure event handling from trait objects to enum pattern

- Convert UnifiedEvent from trait object (Box<dyn UnifiedEvent>) to concrete enum type
  - Remove match_event! macro in favor of native match expressions
  - Simplify event metadata access: event.event_type() -> event.metadata().event_type
  - Unify event callback signatures: Fn(Box<dyn UnifiedEvent>) -> Fn(UnifiedEvent)
  - Update all example code to use the new enum-based event system
  - Optimize type system to reduce runtime overhead and improve type safety

  Affected scope:
  - Core event parser and processor
  - All protocol event definitions (PumpFun, PumpSwap, Bonk, Raydium series, etc.)
  - gRPC and Shred streaming modules
  - All example code

examples/parse_tx_events.rs

@@ -101,7 +101,7 @@ async fn get_single_transaction_details(signature_str: &str) -> Result<()> {
                 .parse_encoded_confirmed_transaction_with_status_meta(
                     signature,
                     transaction,
-                    Arc::new(move |event: &Box<dyn UnifiedEvent>| {
+                    Arc::new(move |event: &UnifiedEvent| {
                         println!("{:?}\n", event);
                     }),
                 )