Declare Forgejo token config as secret ref

tests/manifest.spec.ts

@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest";
+import manifest from "../src/manifest.js";
+
+describe("manifest", () => {
+  it("declares the Forgejo token config as a secret ref", () => {
+    const tokenField = manifest.instanceConfigSchema?.properties?.forgejoTokenRef;
+
+    expect(tokenField).toMatchObject({
+      type: "string",
+      format: "secret-ref"
+    });
+  });
+});