fix minimum rent error and lamports conversion

programs/descro/src/error.rs

@@ -16,4 +16,6 @@ pub enum EscrowError {
     DisputeTimeoutNotReached,
     #[msg("Vault balance is insufficient for the requested escrow amount")]
     InsufficientVaultBalance,
+    #[msg("Amount must be at least rent-exempt minimum for the vault (~890880 lamports)")]
+    AmountBelowRentMinimum,
 }

programs/descro/src/instructions/create_escrow.rs

@@ -1,5 +1,6 @@
 use anchor_lang::prelude::*;
 use crate::state::{EscrowAccount, EscrowState};
+use crate::EscrowError;
 
 #[derive(Accounts)]
 #[instruction(amount: u64, dispute_resolver: Option<Pubkey>, escrow_id: u64)]
@@ -36,6 +37,9 @@ pub fn handler(
     dispute_resolver: Option<Pubkey>,
     escrow_id: u64,
 ) -> Result<()> {
+    let rent_min = Rent::get()?.minimum_balance(0);
+    require!(amount >= rent_min, EscrowError::AmountBelowRentMinimum);
+
     let escrow = &mut ctx.accounts.escrow_account;
     escrow.seller = ctx.accounts.seller.key();
     escrow.buyer = ctx.accounts.buyer.key();