refactor: remove LockerTable component, enhance ItemTable and LoanTable with CRUD functionality, and implement AddItemForm for item creation

admin/src/components/AddItemForm.tsx

@@ -0,0 +1,84 @@
+import React from "react";
+import { Button, Card, Field, Input, Stack } from "@chakra-ui/react";
+import { createItem } from "@/utils/userActions";
+
+type AddItemFormProps = {
+  onClose: () => void;
+  alert: (
+    status: "success" | "error",
+    message: string,
+    description: string
+  ) => void;
+};
+
+const AddItemForm: React.FC<AddItemFormProps> = ({ onClose, alert }) => {
+  return (
+    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm p-4">
+      <Card.Root maxW="sm">
+        <Card.Header>
+          <Card.Title>Neuen Gegenstand erstellen</Card.Title>
+          <Card.Description>
+            Füllen Sie das folgende Formular aus, um einen Gegenstand zu
+            erstellen.
+          </Card.Description>
+        </Card.Header>
+        <Card.Body>
+          <Stack gap="4" w="full">
+            <Field.Root>
+              <Field.Label>Gegenstandsname</Field.Label>
+              <Input id="item_name" placeholder="z.B. Laptop" />
+            </Field.Root>
+            <Field.Root>
+              <Field.Label>Ausleih-Berechtigung (Rolle)</Field.Label>
+              <Input
+                id="can_borrow_role"
+                type="number"
+                placeholder="Zahl (z.B. 2)"
+              />
+            </Field.Root>
+          </Stack>
+        </Card.Body>
+        <Card.Footer justifyContent="flex-end" gap="2">
+          <Button variant="outline" onClick={onClose}>
+            Abbrechen
+          </Button>
+          <Button
+            variant="solid"
+            onClick={async () => {
+              const name =
+                (
+                  document.getElementById("item_name") as HTMLInputElement
+                )?.value.trim() || "";
+              const role = Number(
+                (document.getElementById("can_borrow_role") as HTMLInputElement)
+                  ?.value
+              );
+
+              if (!name || Number.isNaN(role)) return;
+
+              const res = await createItem(name, role);
+              if (res.success) {
+                alert(
+                  "success",
+                  "Gegenstand erstellt",
+                  "Der Gegenstand wurde erfolgreich erstellt."
+                );
+                onClose();
+              } else {
+                alert(
+                  "error",
+                  "Fehler",
+                  "Der Gegenstand konnte nicht erstellt werden."
+                );
+              }
+            }}
+          >
+            Erstellen
+          </Button>
+        </Card.Footer>
+      </Card.Root>
+    </div>
+  );
+};
+
+export default AddItemForm;