feat(maestro): default structured view on for ACP agents

A Claude Code or Codex spawn now asks for the structured view unless the
operator says otherwise: the two spawn forms open with the box ticked and
`maestro spawn` takes `--terminal` to opt out. Once the operator works the
toggle, a command change no longer re-ticks it under them.

The support predicate moves to `maestro_protocol::display` so all three
clients gate on the same resolution.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

web/src/spawnFormStructured.test.ts

@@ -44,7 +44,7 @@ describe("spawn form structured view", () => {
     vi.unstubAllGlobals();
   });
 
-  it("is default-off and shown for resolved Claude Code and Codex commands", async () => {
+  it("is default-on and shown for resolved Claude Code and Codex commands", async () => {
     stubApi();
     handle = createSpawnForm({ onSuccess() {} });
     document.body.appendChild(handle.el);
@@ -57,7 +57,7 @@ describe("spawn form structured view", () => {
     handle.el.querySelector<HTMLButtonElement>(".wt-toggle")!.click();
     expect(disclosure.hidden).toBe(false);
     expect(wrap.hidden).toBe(false);
-    expect(checkbox.checked).toBe(false);
+    expect(checkbox.checked).toBe(true);
 
     const custom = handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!;
     custom.click();
@@ -65,13 +65,34 @@ describe("spawn form structured view", () => {
     command.value = "FOO=1 /usr/local/bin/codex";
     command.dispatchEvent(new Event("input"));
     expect(wrap.hidden).toBe(false);
+    expect(checkbox.checked).toBe(true);
 
     command.value = "opencode";
     command.dispatchEvent(new Event("input"));
     expect(wrap.hidden).toBe(true);
+    expect(checkbox.checked).toBe(false);
   });
 
-  it("clears a checked value when Codex changes to an unsupported command", async () => {
+  it("keeps an unchecked box unchecked across a command change", async () => {
+    stubApi();
+    handle = createSpawnForm({ onSuccess() {} });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    const checkbox = handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!;
+    expect(checkbox.checked).toBe(true);
+    checkbox.click();
+    expect(checkbox.checked).toBe(false);
+
+    handle.el.querySelector<HTMLButtonElement>('[data-id="custom"]')!.click();
+    const command = handle.el.querySelector<HTMLInputElement>(".cmd-raw")!;
+    command.value = "codex";
+    command.dispatchEvent(new Event("input"));
+
+    expect(checkbox.checked).toBe(false);
+  });
+
+  it("clears the checked default when Codex changes to an unsupported command", async () => {
     stubApi();
     handle = createSpawnForm({ onSuccess() {} });
     document.body.appendChild(handle.el);
@@ -83,7 +104,6 @@ describe("spawn form structured view", () => {
     command.dispatchEvent(new Event("input"));
 
     const checkbox = handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!;
-    checkbox.click();
     expect(checkbox.checked).toBe(true);
 
     command.value = "opencode";
@@ -93,7 +113,7 @@ describe("spawn form structured view", () => {
     expect(checkbox.checked).toBe(false);
   });
 
-  it.each(["claude", "codex"])("emits Structured for a selected %s command", async (tool) => {
+  it.each(["claude", "codex"])("emits Structured for a %s command by default", async (tool) => {
     const requests = stubApi();
     handle = createSpawnForm({
       seed: { cwd: "/srv/work", cwdRawVisible: true, worktreeEnabled: false },
@@ -109,7 +129,6 @@ describe("spawn form structured view", () => {
       command.dispatchEvent(new Event("input"));
     }
 
-    handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!.click();
     handle.el.requestSubmit();
     await drain();
 
@@ -119,4 +138,21 @@ describe("spawn form structured view", () => {
       view: "Structured",
     });
   });
+
+  it("emits no view once the operator unticks the box", async () => {
+    const requests = stubApi();
+    handle = createSpawnForm({
+      seed: { cwd: "/srv/work", cwdRawVisible: true, worktreeEnabled: false },
+      onSuccess() {},
+    });
+    document.body.appendChild(handle.el);
+    await drain();
+
+    handle.el.querySelector<HTMLInputElement>("input[name=structured_view]")!.click();
+    handle.el.requestSubmit();
+    await drain();
+
+    expect(requests).toHaveLength(1);
+    expect(JSON.parse(String(requests[0].body)).view).toBeUndefined();
+  });
 });