feat: establish TypeScript-aware frontend tooling

tests/component/sample-resource-page.test.jsx

@@ -7,9 +7,10 @@ import { SampleResourcePage } from "../../src/sample/contract-fixture/sample-res
 
 describe("removable sample feature page", () => {
   it("renders the API-to-view-model result through AsyncSurface", async () => {
+    /** @type {Parameters<typeof SampleResourcePage>[0]["facade"]} */
     const facade = {
       listResources: async () => ({
-        ok: true,
+        ok: /** @type {const} */ (true),
         value: [
           {
             resourceId: "resource-1",
@@ -18,7 +19,14 @@ describe("removable sample feature page", () => {
           },
         ],
       }),
-      createResource: async () => ({ ok: true, value: {} }),
+      createResource: async () => ({
+        ok: /** @type {const} */ (true),
+        value: {
+          resourceId: "resource-created",
+          title: "Created",
+          createdAtLabel: null,
+        },
+      }),
     };
     render(<SampleResourcePage facade={facade} />);
 
@@ -27,9 +35,10 @@ describe("removable sample feature page", () => {
   });
 
   it("renders normalized terminal errors without raw DTO fields", async () => {
+    /** @type {Parameters<typeof SampleResourcePage>[0]["facade"]} */
     const facade = {
       listResources: async () => ({
-        ok: false,
+        ok: /** @type {const} */ (false),
         error: {
           kind: "SERVER_FAILURE",
           code: "SERVER_FAILURE",
@@ -40,7 +49,14 @@ describe("removable sample feature page", () => {
           action: "retry",
         },
       }),
-      createResource: async () => ({ ok: true, value: {} }),
+      createResource: async () => ({
+        ok: /** @type {const} */ (true),
+        value: {
+          resourceId: "resource-created",
+          title: "Created",
+          createdAtLabel: null,
+        },
+      }),
     };
     render(<SampleResourcePage facade={facade} />);