feat(turbo-gen): templates for gen realtime handler

turbo/generators/templates/realtime/handler/handler.test.ts.hbs

@@ -0,0 +1,17 @@
+// packages/{{kebabCase feature}}/src/realtime/handlers/on-{{kebabCase channelSlug}}.handler.test.ts
+import { describe, it, expect } from "vitest";
+import { on{{pascalCase channelSlug}}Handler } from "@/realtime/handlers/on-{{kebabCase channelSlug}}.handler";
+
+describe("on{{pascalCase channelSlug}}Handler", () => {
+  it("returns a function (factory shape)", () => {
+    const handler = on{{pascalCase channelSlug}}Handler();
+    expect(typeof handler).toBe("function");
+  });
+
+  it("does not throw on a valid stub input", async () => {
+    const handler = on{{pascalCase channelSlug}}Handler();
+    await expect(
+      handler({} as never, { userId: "u1", roles: [] }),
+    ).resolves.toBeUndefined();
+  });
+});