feat: add calendar widget (#663)

* feat: add calendar widget

* feat: add artifacts to gitignore

packages/widgets/src/calendar/serverData.ts

@@ -0,0 +1,35 @@
+"use server";
+
+import type { RouterOutputs } from "@homarr/api";
+import { api } from "@homarr/api/server";
+
+import type { WidgetProps } from "../definition";
+
+export default async function getServerDataAsync({ integrationIds, itemId }: WidgetProps<"calendar">) {
+  if (!itemId) {
+    return {
+      initialData: [],
+    };
+  }
+  try {
+    const data = await api.widget.calendar.findAllEvents({
+      integrationIds,
+      itemId,
+    });
+
+    return {
+      initialData: data
+        .filter(
+          (
+            item,
+          ): item is Exclude<Exclude<RouterOutputs["widget"]["calendar"]["findAllEvents"][number], null>, undefined> =>
+            item !== null && item !== undefined,
+        )
+        .flatMap((item) => item.data),
+    };
+  } catch (error) {
+    return {
+      initialData: [],
+    };
+  }
+}