Pair displays at the platform's own /display/setup, with or without modules

Displays are platform-owned, but a screen could only start pairing on a
module's display page: every pairing request named a module, so an
installation with no module that uses displays could not set one up.

- /display/setup is the platform's own display page, served whenever
  the deployment has device support, whatever is installed. It pairs a
  platform display with no module. Once paired, it opens the module it
  is set to show; with none set, it shows its name and waits, rechecking
  so it stays alive and notices revocation. "setup" is now a reserved
  module id.
- Migration core:0009_platform_display_pairing lets a pairing request
  name no module. It relaxes module_id and permission_id and adds a
  both-or-neither check. It is additive and destroys nothing.
- POST /api/v1/device-pairing/requests accepts {} for a platform
  display. Approval accepts an optional moduleId, so the administrator
  can choose an installed display module and the device gets that
  module's declared permission. A module display's own request can't be
  redirected.
- GET /api/v1/device-pairing/self lets a paired device describe itself:
  its name and the module displays it may show. It renews the device's
  cookie.
- GET /api/v1/devices/setup is replaced by
  GET /api/v1/devices/display-modules: the modules a display can be set
  to show.
- Settings -> Displays always offers the /display/setup address, Copy
  setup link and Add display. Add display has an optional "Show on this
  screen" choice, and each paired display says what it shows.
- /display/<module-id> is unchanged, so released Signage 0.1.5 works as
  before.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

scripts/lib/deploy-smoke-browser.mjs

@@ -600,33 +600,112 @@ check(
   ),
   "the sidebar is navigation only, and arriving at Displays focuses no field",
 );
-// ADR 0065: how to set up a new screen, in one place — the platform display page of every module
-// that uses displays, on the API origin where the display host lives, with Add display right under
-// it; or a plain note, and no Add display, when no installed module uses displays.
+// ADR 0065: how to set up a new screen, in one place — the platform's own /display/setup on the API
+// origin, whatever is installed, with Add display right under it.
 check(
   await waitFor(
-    `${selector("display-setup")} && !${selector("display-setup-failed")} && (${selector("display-setup-none")} || (${selector("display-setup")}.contains(${selector("add-display")}) && [...document.querySelectorAll('[data-testid="display-setup-url"]')].every((element) => element.textContent.startsWith(${JSON.stringify(`${apiOrigin}/display/`)}))))`,
+    `${selector("display-setup")}?.contains(${selector("add-display")}) && ${selector("display-setup-url")}?.textContent === ${JSON.stringify(`${apiOrigin}/display/setup`)}`,
     "the display setup steps",
   ),
-  "Settings → Displays explains how to set up a new screen, from the platform's own display page",
+  "Settings → Displays sets up a new screen at the platform's own /display/setup, with Add display",
 );
-const displayModuleInstalled = !(await evaluate(`Boolean(${selector("display-setup-none")})`));
-if (displayModuleInstalled) {
-  await evaluate(`${selector("add-display")}.click()`);
-  check(
-    await waitFor(
-      `${selector("add-display-dialog")} && document.activeElement === ${selector("device-pairing-code-input")}`,
-      "the Add display dialog with its code field focused",
-    ),
-    "Add display opens a dialog that focuses the pairing code only once asked",
-  );
-  await evaluate(`${selector("add-display-cancel")}.click()`);
-  await waitFor(`!${selector("add-display-dialog")}`, "the Add display dialog closing");
-} else {
-  check(
-    !(await evaluate(`Boolean(${selector("add-display")})`)),
-    "with no module that uses displays, Settings → Displays offers no Add display that could only fail",
-  );
+await evaluate(`${selector("add-display")}.click()`);
+check(
+  await waitFor(
+    `${selector("add-display-dialog")} && document.activeElement === ${selector("device-pairing-code-input")}`,
+    "the Add display dialog with its code field focused",
+  ),
+  "Add display opens a dialog that focuses the pairing code only once asked",
+);
+await evaluate(`${selector("add-display-cancel")}.click()`);
+await waitFor(`!${selector("add-display-dialog")}`, "the Add display dialog closing");
+
+// ADR 0065, end to end: a new screen — its own browser context, holding no session, as a real
+// screen would — opens the platform's /display/setup, shows a code, and is added through the real
+// Settings form. It needs no module: chosen, it opens that module's display by itself; not chosen,
+// it shows its name and waits.
+{
+  const { browserContextId } = await cdp.send("Target.createBrowserContext", {});
+  const kiosk = await cdp.send("Target.createTarget", { browserContextId, url: "about:blank" });
+  const { sessionId: kioskSession } = await cdp.send("Target.attachToTarget", {
+    flatten: true,
+    targetId: kiosk.targetId,
+  });
+  const kioskEvaluate = async (expression) => {
+    const result = await cdp.send(
+      "Runtime.evaluate",
+      { awaitPromise: true, expression, returnByValue: true },
+      kioskSession,
+    );
+    return result.exceptionDetails ? undefined : result.result.value;
+  };
+  const kioskWaitFor = async (expression) => {
+    const deadline = Date.now() + timeoutMs;
+    while (Date.now() < deadline) {
+      if (await kioskEvaluate(`Boolean(${expression})`).catch(() => false)) {
+        return true;
+      }
+      await new Promise((resolve) => setTimeout(resolve, 250));
+    }
+    return false;
+  };
+  await cdp.send("Page.navigate", { url: `${apiOrigin}/display/setup` }, kioskSession);
+  const shown = (await kioskWaitFor(
+    `/^[0-9]{6}$/.test(${selector("display-pairing-code")}?.textContent ?? "")`,
+  ))
+    ? await kioskEvaluate(`${selector("display-pairing-code")}.textContent`)
+    : undefined;
+  check(shown !== undefined, "a new screen at /display/setup shows a six-digit pairing code");
+  if (shown !== undefined) {
+    await evaluate(`${selector("add-display")}.click()`);
+    await waitFor(selector("device-pairing-code-input"), "the Add display code field");
+    await evaluate(`(() => {
+      const input = ${selector("device-pairing-code-input")};
+      Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, "value").set.call(input, ${JSON.stringify(shown)});
+      input.dispatchEvent(new Event("input", { bubbles: true }));
+      input.form.requestSubmit();
+    })()`);
+    check(
+      await waitFor(
+        `${selector("device-pairing-found")}?.textContent.includes("A new screen is waiting to be paired")`,
+        "the platform screen found by its code",
+      ),
+      "Add display finds the screen from /display/setup as a new platform display, with no module",
+    );
+    const chosen = await evaluate(`(() => {
+      const name = ${selector("device-pairing-name")};
+      Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, "value").set.call(name, "Smoke platform display");
+      name.dispatchEvent(new Event("input", { bubbles: true }));
+      const shows = ${selector("device-pairing-shows")};
+      const option = shows ? [...shows.options].find((candidate) => candidate.value !== "") : undefined;
+      if (option) {
+        Object.getOwnPropertyDescriptor(HTMLSelectElement.prototype, "value").set.call(shows, option.value);
+        shows.dispatchEvent(new Event("change", { bubbles: true }));
+      }
+      return option ? option.value : "";
+    })()`);
+    await waitFor(`!${selector("device-pairing-approve")}?.disabled`, "Pair display enabled");
+    await evaluate(`${selector("device-pairing-approve")}.click()`);
+    check(
+      await waitFor(
+        `!${selector("add-display-dialog")} && [...document.querySelectorAll('[data-testid^="device-"]')].some((card) => card.textContent.includes("Smoke platform display"))`,
+        "the new platform display in the list",
+      ),
+      "the paired platform display appears under Paired displays without a reload",
+    );
+    check(
+      await kioskWaitFor(
+        chosen === ""
+          ? `${selector("display-setup-waiting-headline")}?.textContent === "Smoke platform display"`
+          : `location.pathname === ${JSON.stringify(`/display/${chosen}`)}`,
+      ),
+      chosen === ""
+        ? "with no module to show, the paired screen shows its name and waits"
+        : "the paired screen opens the module display it was set to show, by itself",
+    );
+  }
+  await cdp.send("Target.closeTarget", { targetId: kiosk.targetId });
+  await cdp.send("Target.disposeBrowserContext", { browserContextId });
 }
 await navigate(`${dashboardOrigin}/settings/discover`);
 check(
@@ -698,20 +777,18 @@ check(
   "choosing a page from the drawer releases the page lock",
 );
 // ADR 0065: on a phone the pairing code is typed at 16px or more, so iOS Safari does not zoom.
-if (displayModuleInstalled) {
-  await navigate(`${dashboardOrigin}/settings/displays`);
-  await waitFor(selector("add-display"), "Settings → Displays on a phone");
-  await evaluate(`${selector("add-display")}.click()`);
-  check(
-    await waitFor(
-      `${selector("device-pairing-code-input")} && parseFloat(getComputedStyle(${selector("device-pairing-code-input")}).fontSize) >= 16`,
-      "the pairing code field's size on a phone",
-    ),
-    "the pairing code field is at least 16px on a phone, so iOS does not zoom into it",
-  );
-  await evaluate(`${selector("add-display-cancel")}.click()`);
-  await waitFor(`!${selector("add-display-dialog")}`, "the Add display dialog closing on a phone");
-}
+await navigate(`${dashboardOrigin}/settings/displays`);
+await waitFor(selector("add-display"), "Settings → Displays on a phone");
+await evaluate(`${selector("add-display")}.click()`);
+check(
+  await waitFor(
+    `${selector("device-pairing-code-input")} && parseFloat(getComputedStyle(${selector("device-pairing-code-input")}).fontSize) >= 16`,
+    "the pairing code field's size on a phone",
+  ),
+  "the pairing code field is at least 16px on a phone, so iOS does not zoom into it",
+);
+await evaluate(`${selector("add-display-cancel")}.click()`);
+await waitFor(`!${selector("add-display-dialog")}`, "the Add display dialog closing on a phone");
 await send("Emulation.setDeviceMetricsOverride", {
   deviceScaleFactor: 1,
   height: 1080,