CRITICAL FIX: Always show malware scanner menu (no installation guide gate)

FIXED:
- detect_scanners() no longer blocks menu when scanners aren't installed
- Removed show_scanner_installation_guide() call from detection
- Menu always displays with option 9 'Install all scanners'
- User can now select which scanners to install directly from menu

BEHAVIOR CHANGE:
- Before: No scanners → installation guide → exit code 1 → no menu
- After: No scanners → menu with install option → user can install from there

This restores the original user experience where the menu is always available.

modules/security/malware-scanner.sh

@@ -94,13 +94,9 @@ detect_scanners() {
         available_scanners+=("rkhunter")
     fi
 
-    if [ ${#available_scanners[@]} -eq 0 ]; then
-        echo -e "${RED}No malware scanners detected!${NC}"
-        echo ""
-        show_scanner_installation_guide
-        return 1
-    fi
-
+    # Note: If no scanners are found, available_scanners array will be empty
+    # Menu option 9 allows installation, so we don't exit here
+    # Just return success to allow menu to display
     return 0
 }