fix: Add needsVerification field to ClosePositionResult interface

- Added optional needsVerification?: boolean to ClosePositionResult
- Fixes TypeScript build error from commit c607a66
- Required for position close verification logic
- Allows Position Manager to keep monitoring if close not yet propagated

lib/drift/orders.ts

@@ -45,6 +45,7 @@ export interface ClosePositionResult {
   closePrice?: number
   closedSize?: number
   realizedPnL?: number
+  needsVerification?: boolean
   error?: string
 }