refactor: Major SDK architecture refactoring and API consolidation

- Consolidate separate buy/sell modules into unified trading interface
- Remove protocol-specific buy/sell files (bonk, pumpfun, pumpswap)
- Add new trading constants and utility functions
- Simplify API with unified buy/sell methods supporting multiple protocols
- Enhance documentation with comprehensive examples and usage guides
- Add balance checking and token account management utilities
- Improve code organization and maintainability

src/constants/mod.rs

@@ -1,17 +1,11 @@
+pub mod bonk;
 pub mod pumpfun;
 pub mod pumpswap;
-pub mod bonk;
 pub mod swqos;
-
-pub mod trade_type {
-  pub const COPY_BUY: &'static str = "copy_buy";
-  pub const COPY_SELL: &'static str = "copy_sell";
-  pub const SNIPER_BUY: &'static str = "sniper_buy";
-  pub const SNIPER_SELL: &'static str = "sniper_sell";
-}
+pub mod trade;
 
 pub mod trade_platform {
-  pub const PUMPFUN: &'static str = "pumpfun";
-  pub const PUMPFUN_SWAP: &'static str = "pumpswap";
-  pub const BONK: &'static str = "bonk";
-}
+    pub const PUMPFUN: &'static str = "pumpfun";
+    pub const PUMPFUN_SWAP: &'static str = "pumpswap";
+    pub const BONK: &'static str = "bonk";
+}