fix: Implement Associated Token Account for USDC withdrawals

- Fixed PublicKey undefined error (derive from DRIFT_WALLET_PRIVATE_KEY)
- Implemented ATA resolution using @solana/spl-token
- Added comprehensive debug logging for withdrawal flow
- Fixed AccountOwnedByWrongProgram error (need ATA not wallet address)
- Successfully tested .58 withdrawal with on-chain confirmation
- Updated .env with TOTAL_WITHDRAWN and LAST_WITHDRAWAL_TIME tracking

Key changes:
- lib/drift/withdraw.ts: Added getAssociatedTokenAddress() for USDC ATA
- tsconfig.json: Excluded archive folders from compilation
- package.json: Added bn.js as direct dependency

Transaction: 4drNfMR1xBosGCQtfJ2a4r6oEawUByrT6L7Thyqu6QQWz555hX3QshFuJqiLZreL7KrheSgTdCEqMcXP26fi54JF
Wallet: 3dG7wayp7b9NBMo92D2qL2sy1curSC4TTmskFpaGDrtA
USDC ATA: 8ZEMwErnwxPNNNHJigUcMfrkBG14LCREDdKbqKm49YY7

lib/drift/withdraw.ts

@@ -5,8 +5,10 @@
  */
 
 import BN from 'bn.js'
-import { PublicKey } from '@solana/web3.js'
+import { PublicKey, Keypair } from '@solana/web3.js'
+import { getAssociatedTokenAddress, TOKEN_PROGRAM_ID } from '@solana/spl-token'
 import { initializeDriftService } from './client'
+import bs58 from 'bs58'
 
 export interface WithdrawalResult {
   success: boolean
@@ -29,17 +31,62 @@ export async function withdrawFromDrift(
     
     // Convert USD amount to token amount (USDC has 6 decimals)
     // $50.25 → 50,250,000 (raw token amount with 6 decimals)
-    const tokenAmount = new BN(Math.floor(amountUSD * 1_000_000))
+    const rawAmount = Math.floor(amountUSD * 1_000_000)
+    console.log(`📊 Raw amount before BN: ${rawAmount} (type: ${typeof rawAmount})`)
+    const tokenAmount = new BN(rawAmount.toString())
     
     console.log(`📊 Withdrawal details:`)
     console.log(`   Amount: $${amountUSD.toFixed(2)} USDC`)
     console.log(`   Token amount: ${tokenAmount.toString()} (raw with 6 decimals)`)
     console.log(`   Market index: ${usdcMarketIndex}`)
     
-    // Get destination address (default to wallet public key if not specified)
-    const destination = destinationWallet 
-      ? new PublicKey(destinationWallet)
-      : new PublicKey(process.env.WALLET_PUBLIC_KEY!)
+    // Get destination address
+    // Need to get the Associated Token Account (ATA) for USDC, not just the wallet address
+    let walletPublicKey: PublicKey
+    let destination: PublicKey
+    try {
+      if (destinationWallet) {
+        console.log(`🔑 Using provided destination wallet`)
+        walletPublicKey = new PublicKey(destinationWallet)
+      } else {
+        console.log(`🔑 Deriving destination from private key`)
+        // Derive public key from private key (same wallet as trader)
+        const privateKeyStr = process.env.DRIFT_WALLET_PRIVATE_KEY
+        if (!privateKeyStr) {
+          throw new Error('DRIFT_WALLET_PRIVATE_KEY environment variable not set')
+        }
+        console.log(`🔑 Private key length: ${privateKeyStr.length}`)
+        const privateKeyBytes = privateKeyStr.startsWith('[') 
+          ? Uint8Array.from(JSON.parse(privateKeyStr))
+          : bs58.decode(privateKeyStr)
+        console.log(`🔑 Private key bytes length: ${privateKeyBytes.length}`)
+        const keypair = Keypair.fromSecretKey(privateKeyBytes)
+        walletPublicKey = keypair.publicKey
+        console.log(`🔑 Derived wallet public key: ${walletPublicKey.toString()}`)
+      }
+      
+      // USDC mint address on Solana mainnet
+      const usdcMint = new PublicKey('EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v')
+      console.log(`🔑 USDC Mint: ${usdcMint.toString()}`)
+      console.log(`🔑 Wallet public key: ${walletPublicKey.toString()}`)
+      console.log(`🔑 About to call getAssociatedTokenAddress...`)
+      
+      // Get the Associated Token Account for USDC
+      destination = await getAssociatedTokenAddress(
+        usdcMint,
+        walletPublicKey,
+        false, // allowOwnerOffCurve
+        TOKEN_PROGRAM_ID
+      )
+      
+      console.log(`✅ Got ATA successfully!`)
+      console.log(`   Wallet: ${walletPublicKey.toString()}`)
+      console.log(`   USDC ATA: ${destination.toString()}`)
+      
+    } catch (keyError: any) {
+      console.error(`❌ Failed to get destination address:`, keyError)
+      throw new Error(`Failed to derive destination address: ${keyError?.message || 'Unknown error'}`)
+    }
     
     console.log(`   Destination: ${destination.toString()}`)