Phase 2: Market context capture at entry

- Added getFundingRate() method to DriftService
- Capture expectedEntryPrice from oracle before order execution
- Capture fundingRateAtEntry from Drift Protocol
- Save market context fields to database (expectedEntryPrice, fundingRateAtEntry)
- Calculate entry slippage percentage in createTrade()
- Fixed template literal syntax errors in execute endpoint

Database fields populated:
- expectedEntryPrice: Oracle price before order
- entrySlippagePct: Calculated from entrySlippage
- fundingRateAtEntry: Current funding rate from Drift

Next: Phase 3 (analytics API) or test market context on next trade

lib/drift/client.ts

@@ -233,6 +233,31 @@ export class DriftService {
     }
   }
 
+  /**
+   * Get funding rate for a perpetual market
+   * Returns funding rate as percentage (e.g., 0.01 = 1% per 8 hours)
+   */
+  async getFundingRate(marketIndex: number): Promise<number | null> {
+    this.ensureInitialized()
+    
+    try {
+      const perpMarketAccount = this.driftClient!.getPerpMarketAccount(marketIndex)
+      if (!perpMarketAccount) {
+        console.warn(`⚠️ No perp market account found for index ${marketIndex}`)
+        return null
+      }
+      
+      // Funding rate is stored as a number with 9 decimals (1e9)
+      // Convert to percentage
+      const fundingRate = Number(perpMarketAccount.amm.lastFundingRate) / 1e9
+      
+      return fundingRate
+    } catch (error) {
+      console.error(`❌ Failed to get funding rate for market ${marketIndex}:`, error)
+      return null
+    }
+  }
+
   /**
    * Get account health (margin ratio)
    */