refactor: Replace global address lookup table cache with direct fetch approach

Replace the global AddressLookupTableCache with a direct fetch function to simplify address lookup table management. This change improves code maintainability by removing global state and makes the API more explicit.

Key changes:
- Remove AddressLookupTableCache and AddressLookupManager
- Add new fetch_address_lookup_table_account function
- Update TradeBuyParams and TradeSellParams to use AddressLookupTableAccount instead of Pubkey
- Update all examples to use the new direct fetch approach
- Update documentation to reflect the simplified workflow

docs/NONCE_CACHE.md

@@ -57,7 +57,7 @@ let buy_params = sol_trade_sdk::TradeBuyParams {
     slippage_basis_points: Some(100),
     recent_blockhash: Some(recent_blockhash),
     extension_params: Box::new(PumpFunParams::from_trade(&trade_info, None)),
-    lookup_table_key: None,
+    address_lookup_table_account: None,
     wait_transaction_confirmed: true,
     create_wsol_ata: false,
     close_wsol_ata: false,