solana: use custody balance (#125)

Co-authored-by: A5 Pickle <a5-pickle@users.noreply.github.com>

Author: a5-pickle

solana/programs/matching-engine/src/composite/mod.rs

@@ -534,7 +534,7 @@ pub struct ClosePreparedOrderResponse<'info> {
         ],
         bump,
     )]
-    pub custody_token: UncheckedAccount<'info>,
+    pub custody_token: Box<Account<'info, token::TokenAccount>>,
 }
 
 impl<'info> VaaDigest for ClosePreparedOrderResponse<'info> {

solana/programs/matching-engine/src/processor/auction/settle/none/mod.rs

@@ -15,7 +15,7 @@ use common::messages::Fill;
 
 struct SettleNoneAndPrepareFill<'ctx, 'info> {
     prepared_order_response: &'ctx mut Account<'info, PreparedOrderResponse>,
-    prepared_custody_token: &'ctx UncheckedAccount<'info>,
+    prepared_custody_token: &'ctx Account<'info, token::TokenAccount>,
     auction: &'ctx mut Account<'info, Auction>,
     fee_recipient_token: &'ctx Account<'info, token::TokenAccount>,
     custodian: &'ctx CheckedCustodian<'info>,
@@ -101,7 +101,7 @@ fn settle_none_and_prepare_fill(
     });
 
     Ok(SettledNone {
-        user_amount: prepared_order_response.amount_in.saturating_sub(fee),
+        user_amount: prepared_custody_token.amount.saturating_sub(fee),
         fill: Fill {
             source_chain: prepared_order_response.source_chain,
             order_sender: prepared_order_response.sender,