feat: Hybrid RPC strategy (Helius init + Alchemy trades)

CRITICAL: Fix rate limiting by using dual RPC approach

Problem:
- Helius RPC gets overwhelmed during trade execution (429 errors)
- Exit orders fail to place, leaving positions UNPROTECTED
- No on-chain TP/SL orders = unlimited risk if container crashes

Solution: Hybrid RPC Strategy
- Helius for Drift SDK initialization (handles burst subscriptions well)
- Alchemy for trade operations (better sustained rate limits)
- Falls back to Helius if Alchemy not configured

Implementation:
- DriftService now has two connections: connection (Helius) + tradeConnection (Alchemy)
- Added getTradeConnection() method for trade operations
- Updated openPosition() and closePosition() to use trade connection
- Added ALCHEMY_RPC_URL to .env (optional, falls back to Helius)

Benefits:
- Helius: 0 subscription errors during init (proven reliable for SDK setup)
- Alchemy: 300M compute units/month for sustained trade operations
- Best of both worlds: reliable init + reliable trades

Files:
- lib/drift/client.ts: Dual connection support
- lib/drift/orders.ts: Use getTradeConnection() for confirmations
- .env: Added ALCHEMY_RPC_URL

Testing: Deploy and execute test trade to verify orders place successfully

lib/drift/client.ts

@@ -17,12 +17,14 @@ interface ManualWallet {
 
 export interface DriftConfig {
   rpcUrl: string
+  alchemyRpcUrl?: string  // Optional: Use Alchemy for trade operations (better sustained rate limits)
   walletPrivateKey: string
   env: 'mainnet-beta' | 'devnet'
 }
 
 export class DriftService {
   private connection: Connection
+  private tradeConnection: Connection  // Separate connection for trade operations (uses Alchemy if available)
   private wallet: ManualWallet
   private keypair: Keypair
   private driftClient: DriftClient | null = null
@@ -32,8 +34,21 @@ export class DriftService {
   private reconnectIntervalMs: number = 4 * 60 * 60 * 1000 // 4 hours (prevent memory leak)
 
   constructor(private config: DriftConfig) {
+    // Helius connection for Drift SDK initialization (handles burst subscriptions well)
     this.connection = new Connection(config.rpcUrl, 'confirmed')
     
+    // Alchemy connection for trade operations (better sustained rate limits)
+    // Falls back to Helius if Alchemy not configured
+    this.tradeConnection = config.alchemyRpcUrl 
+      ? new Connection(config.alchemyRpcUrl, 'confirmed')
+      : this.connection
+    
+    if (config.alchemyRpcUrl) {
+      console.log('🔀 Hybrid RPC mode: Helius for init, Alchemy for trades')
+    } else {
+      console.log('📡 Single RPC mode: Helius for all operations')
+    }
+    
     // Create wallet from private key
     // Support both formats:
     // 1. JSON array: [91,24,199,...] (from Phantom export as array)
@@ -233,6 +248,21 @@ export class DriftService {
     }
   }
 
+  /**
+   * Get the Solana connection (Helius - for SDK operations)
+   */
+  getConnection(): Connection {
+    return this.connection
+  }
+
+  /**
+   * Get the trade connection (Alchemy if configured, otherwise Helius)
+   * Use this for all trade operations (open, close, place orders)
+   */
+  getTradeConnection(): Connection {
+    return this.tradeConnection
+  }
+
   /**
    * Get current USDC balance
    */
@@ -465,6 +495,7 @@ export function getDriftService(): DriftService {
   if (!driftServiceInstance) {
     const config: DriftConfig = {
       rpcUrl: process.env.SOLANA_RPC_URL || 'https://api.mainnet-beta.solana.com',
+      alchemyRpcUrl: process.env.ALCHEMY_RPC_URL, // Optional: Alchemy for trade operations
       walletPrivateKey: process.env.DRIFT_WALLET_PRIVATE_KEY || '',
       env: (process.env.DRIFT_ENV as 'mainnet-beta' | 'devnet') || 'mainnet-beta',
     }