feat: upgrade to v2.0.0 with major dependency updates

- Upgrade Solana dependencies from 2.3.x to 3.0.0 series
  - Upgrade solana-streamer-sdk from 0.4.13 to 0.5.0
  - Upgrade yellowstone-grpc from 8.0.0 to 9.0.0
  - Add new SPL token utility modules (spl_token.rs, spl_token_2022.rs,
  spl_associated_token_account.rs)
  - Remove deprecated gRPC protocol definitions (protos/ directory)
  - Remove event_subscription example and update all example dependencies
  - Update README documentation to reflect v2.0.0 changes
  - Refactor imports to use new dependency structure across examples

  BREAKING CHANGES:
  - Solana SDK upgraded to 3.0.0 with API changes
  - Removed gRPC protocol definitions
  - Updated import paths for SPL token operations

src/lib.rs

@@ -1,7 +1,6 @@
 pub mod common;
 pub mod constants;
 pub mod instruction;
-pub mod protos;
 pub mod swqos;
 pub mod trading;
 pub mod utils;
@@ -30,7 +29,6 @@ use rustls::crypto::{ring::default_provider, CryptoProvider};
 use solana_sdk::hash::Hash;
 use solana_sdk::signer::Signer;
 use solana_sdk::{pubkey::Pubkey, signature::Keypair, signature::Signature};
-pub use solana_streamer_sdk;
 use std::sync::Arc;
 
 /// Type of the token to buy