fix(integrations): preserve Nextcloud subpaths (#6786)

* fix(integrations): preserve Nextcloud subpaths

* Keep existing Nextcloud DAV endpoints intact

---------

Co-authored-by: Artur <145776561+arturict@users.noreply.github.com>
Co-authored-by: arturict <arturict@users.noreply.github.com>

packages/integrations/src/nextcloud/test/nextcloud-url.spec.ts

@@ -0,0 +1,29 @@
+import { describe, expect, test } from "vitest";
+
+import { createNextcloudCalendarServerUrl } from "../nextcloud-url";
+
+describe("createNextcloudCalendarServerUrl", () => {
+  test("uses the DAV endpoint for a root installation", () => {
+    expect(createNextcloudCalendarServerUrl("https://cloud.example.com")).toBe(
+      "https://cloud.example.com/remote.php/dav/",
+    );
+  });
+
+  test("preserves the base path for a subpath installation", () => {
+    expect(createNextcloudCalendarServerUrl("https://example.com/nextcloud")).toBe(
+      "https://example.com/nextcloud/remote.php/dav/",
+    );
+  });
+
+  test("does not duplicate a trailing slash", () => {
+    expect(createNextcloudCalendarServerUrl("https://example.com/nextcloud/")).toBe(
+      "https://example.com/nextcloud/remote.php/dav/",
+    );
+  });
+
+  test("does not duplicate an existing DAV endpoint", () => {
+    expect(createNextcloudCalendarServerUrl("https://example.com/nextcloud/remote.php/dav")).toBe(
+      "https://example.com/nextcloud/remote.php/dav/",
+    );
+  });
+});