Error tests, FK violations fix

- ErrorHandler tests: 77 assertions covering FK extraction, normalization, dedup, edge cases. Fix FK table map for child tables.
- Fix FK violation: (int)null → 0 in createThesis for orientation/ap/finality/license FK columns. Add FK value logging to updateThesis.
- Add CURRENT_ISSUES.md with summary of FK violation, dev debugging, and tag dedup status for next conversation

app/src/Controllers/LicenceController.php

@@ -2,6 +2,7 @@
 
 require_once APP_ROOT . '/src/Database.php';
 require_once APP_ROOT . '/src/Parsedown.php';
+require_once APP_ROOT . '/src/ErrorHandler.php';
 
 class LicenceController
 {
@@ -18,7 +19,7 @@ class LicenceController
             $content = $dbPage ? $dbPage['content'] : '';
             $pageTitle = $dbPage ? $dbPage['title'] : 'Licences';
         } catch (Exception $e) {
-            error_log('Error loading licence page: ' . $e->getMessage());
+            ErrorHandler::log('licence_page', $e);
             $content = '';
             $pageTitle = 'Licences';
         }