feat: soft-delete for teamer accounts

addresses #869dv9br3

src/Validator/Constraints/Application.php

@@ -9,6 +9,8 @@ class Application extends Constraint
 {
     public string $message = 'Diese Bewerbung überlappt sich mit einem deiner bestätigten Einsätze';
 
+    public string $deletedMessage = 'Für einen gelöschten Account können keine Bewerbungen angelegt werden';
+
     public function getTargets(): array|string
     {
         return static::CLASS_CONSTRAINT;

src/Validator/Constraints/ApplicationValidator.php

@@ -21,6 +21,18 @@ class ApplicationValidator extends ConstraintValidator
 
         $teamer = $application->getTeamer();
 
+        // a deleted teamer is excluded from every process, so no new application may be
+        // created for them - not even by an admin acting on their behalf
+        if (true === $teamer->isDeleted()) {
+            $this
+                ->context
+                ->buildViolation($constraint->deletedMessage)
+                ->addViolation()
+            ;
+
+            return;
+        }
+
         if (true === $teamer->isAllowOverlappingApplications()) {
             return;
         }