Fix: Use startup script to create .storage directories at runtime

- Changed from bind mount to named volume for .storage
- Added start.sh script that creates required directories before starting the app
- This prevents ENOENT errors when initializing admin user

start.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# Create .storage directories if they don't exist
+mkdir -p /app/.storage/users
+mkdir -p /app/.storage/bookings
+mkdir -p /app/.storage/treatments
+mkdir -p /app/.storage/availability
+mkdir -p /app/.storage/cancellation-tokens
+
+# Start the application
+exec node server-dist/index.js