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

examples/middleware_system/Cargo.toml

@@ -5,6 +5,8 @@ edition = "2021"
 
 [dependencies]
 sol-trade-sdk = { path = "../.." }
-solana-sdk = "2.3.0"
+solana-streamer-sdk = "0.5.0"
+solana-sdk = "3.0.0"
+solana-commitment-config = { version = "3.0.0", features = ["serde"] }
 tokio = { version = "1", features = ["full"] }
 anyhow = "1.0.79"

examples/middleware_system/src/main.rs

@@ -8,10 +8,8 @@ use sol_trade_sdk::{
     },
     SolanaTrade, TradeTokenType,
 };
-use solana_sdk::{
-    commitment_config::CommitmentConfig, instruction::Instruction, pubkey::Pubkey,
-    signature::Keypair,
-};
+use solana_commitment_config::CommitmentConfig;
+use solana_sdk::{instruction::Instruction, pubkey::Pubkey, signature::Keypair};
 use std::{str::FromStr, sync::Arc};
 
 #[tokio::main]