fix(web): close final workbench interaction gaps

apps/web_v1/scripts/api-client.test.mjs

@@ -50,9 +50,18 @@ test('interrupted successful response body rejects with a stable invalid_respons
 })
 
 test('204 response returns undefined without reading a body', async () => {
-  globalThis.fetch = async () => new Response(null, { status: 204 })
+  let textCalls = 0
+  globalThis.fetch = async () => ({
+    ok: true,
+    status: 204,
+    text: async () => {
+      textCalls += 1
+      throw new Error('204 body must not be read')
+    },
+  })
 
   assert.equal(await apiRequest('/no-content'), undefined)
+  assert.equal(textCalls, 0)
 })
 
 test('explicit void response returns undefined for a non-204 response', async () => {