fix: Health monitor TypeScript error - getAllPositions() method name

- Fixed method call from getPositions() to getAllPositions()
- Health monitor now starts successfully and runs every 30 seconds
- Detects Position Manager monitoring failures within 30 seconds
- Addresses Common Pitfall #77 detection

Tested: Container restart confirmed health monitor operational

lib/health/position-manager-health.ts

@@ -56,7 +56,7 @@ export async function checkPositionManagerHealth(): Promise<HealthCheckResult> {
     
     // Get Drift positions
     const driftService = getDriftService()
-    const positions = await driftService.getPositions()
+    const positions = await driftService.getAllPositions()
     const driftPositions = positions.filter(p => Math.abs(p.size) > 0).length
     
     // CRITICAL CHECK #1: DB has open trades but PM not monitoring