Preserve APK directories in aggressive cleanup for apk update capability

- Keep /var/cache/apk and /lib/apk/db directories but clean files inside
- Allows running 'apk update' in Zero-OS when needed
- Clean cache files and database files but preserve directory structure
- Maintains package management functionality while minimizing size

scripts/lib/alpine.sh

@@ -240,12 +240,26 @@ function alpine_aggressive_cleanup() {
     log_info "Removing static libraries"
     find "${initramfs_dir}" -name "*.a" -type f -delete 2>/dev/null || true
     
-    # Remove APK cache and database backup
-    log_info "Removing APK cache and database backup"
-    safe_rmdir "${initramfs_dir}/var/cache/apk"
-    safe_rmdir "${initramfs_dir}/lib/apk/db"
+    # Clean APK cache and databases but keep directories for apk update capability
+    log_info "Cleaning APK cache and databases (keeping directories for apk update)"
+    
+    # Clean cache files but keep directory structure
+    if [[ -d "${initramfs_dir}/var/cache/apk" ]]; then
+        find "${initramfs_dir}/var/cache/apk" -type f -delete 2>/dev/null || true
+        log_info "✓ Cleaned APK cache files (directory preserved)"
+    fi
+    
+    # Clean database files but keep directories for apk functionality
+    if [[ -d "${initramfs_dir}/lib/apk/db" ]]; then
+        find "${initramfs_dir}/lib/apk/db" -type f -delete 2>/dev/null || true
+        log_info "✓ Cleaned APK database files (directory preserved)"
+    fi
+    
+    # Remove old backup files
     find "${initramfs_dir}/var/lib/apk" -name "*.old" -delete 2>/dev/null || true
     
+    log_info "APK directories preserved for 'apk update' functionality"
+    
     # Remove kernel source and headers if present
     log_info "Removing kernel development files"
     safe_rmdir "${initramfs_dir}/usr/src"