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

src/trading/core/executor.rs

@@ -87,7 +87,7 @@ impl TradeExecutor for GenericTradeExecutor {
             params.payer,
             params.rpc,
             final_instructions,
-            params.lookup_table_key,
+            params.address_lookup_table_account,
             params.recent_blockhash,
             params.durable_nonce,
             if is_buy { params.data_size_limit } else { 0 },