REFACTOR: Class D modules - Panel-specific conditionals

Completed Class D refactoring (panel-specific modules).

MODULES REFACTORED:

1. enable-cphulk.sh (ALREADY COMPLIANT)
   - Already checks SYS_CONTROL_PANEL at startup (line 35)
   - Exits gracefully if not cPanel
   - Shows detected panel in error message
   - All whmapi1 calls only reachable after panel check
   - No changes needed ✅

2. system-health-check.sh (ENHANCED)
   - Already had conditional checks for CPHulk (lines 606, 1706)
   - Enhanced control panel version detection (line 940-947)
   - Now uses SYS_CONTROL_PANEL_VERSION from system-detect.sh
   - Supports cPanel, Plesk, InterWorx version reporting
   - All panel-specific features properly gated

ARCHITECTURE COMPLIANCE:
✅ Panel-specific features wrapped in conditionals
✅ Graceful degradation when feature unavailable
✅ Clear error messages mentioning panel requirements
✅ Uses system-detect.sh variables
✅ All syntax validated

VERIFIED COMPLIANT:
✅ mysql-query-analyzer.sh - Already uses get_user_databases()

TESTING:
- Both modules passed `bash -n` syntax check
- enable-cphulk.sh will exit gracefully on non-cPanel
- system-health-check.sh will skip cPanel features on other panels

PROGRESS UPDATE:
- Class A: ✅ 7 modules (no changes needed)
- Class B: ✅ 6/6 modules COMPLETE
- Class C: ✅ 3/6 modules (bot-analyzer, malware-scanner, mysql-query)
- Class D: ✅ 2/2 modules COMPLETE
- Acronis: ✅ 13 modules (no changes needed)

Total: 31/38 modules architecture-compliant!

Remaining: 7 modules (website error analyzers + WordPress)

modules/diagnostics/system-health-check.sh

@@ -937,12 +937,13 @@ System may be vulnerable" \
         fi
     fi
 
-    # Check for cPanel updates (if cPanel)
-    if [ -f "/usr/local/cpanel/version" ]; then
-        local cpanel_version=$(cat /usr/local/cpanel/version)
-        # Note: We can't easily check if update is available without WHM API
-        # Just record the version
-        echo "cPanel version: $cpanel_version" >> "$TEMP_DIR/system_info.txt"
+    # Check for control panel version
+    if [ "$SYS_CONTROL_PANEL" = "cpanel" ] && [ -n "$SYS_CONTROL_PANEL_VERSION" ]; then
+        echo "cPanel version: $SYS_CONTROL_PANEL_VERSION" >> "$TEMP_DIR/system_info.txt"
+    elif [ "$SYS_CONTROL_PANEL" = "plesk" ] && [ -n "$SYS_CONTROL_PANEL_VERSION" ]; then
+        echo "Plesk version: $SYS_CONTROL_PANEL_VERSION" >> "$TEMP_DIR/system_info.txt"
+    elif [ "$SYS_CONTROL_PANEL" = "interworx" ] && [ -n "$SYS_CONTROL_PANEL_VERSION" ]; then
+        echo "InterWorx version: $SYS_CONTROL_PANEL_VERSION" >> "$TEMP_DIR/system_info.txt"
     fi
 }