A buttons widget: a grid of presses on one message

Several stateless instructions where a single button is one — six presets are
otherwise six tiles to place, six titles to read, and the message they share
repeated six times. Nothing is read back, as for a single button: what these
send is an instruction, and the last one sent is not a state to draw.

Auto-fit columns rather than a configured count: a tile is resized in the
editor and scaled again to whatever panel it hangs on, so how many fit is not
something the document can know.

The editor reads `cfg.buttons` raw rather than through `buttonsOf`, which
drops the blanks — a row being typed into is blank until the first keystroke.

Also carried along by the hooks: the generated SDK was stale (it had no
`RunsReadMetricNames`) and one pre-existing block in `test_panels.py` was
unformatted.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bm2HwnRsTDpeWjSPNJxQd

frontend/tests/widgets.spec.ts

@@ -151,6 +151,20 @@ test.beforeAll(async ({ browser }) => {
         ],
       },
     },
+    {
+      id: "scenes",
+      type: "buttons",
+      title: "Scenes",
+      layout: { lg: { x: 9, y: 0, w: 3, h: 2 } },
+      config: {
+        target: w("mode"),
+        dtype: "str",
+        buttons: [
+          { label: "Night", value: "night" },
+          { label: "Away", value: "away" },
+        ],
+      },
+    },
     {
       id: "lamp",
       type: "switch",
@@ -488,6 +502,12 @@ test("a control reads back what it published", async ({ page }) => {
   await boost.click()
   await expect(boost).toHaveAttribute("aria-pressed", "true")
 
+  // A grid draws one press per entry and publishes the value of the one
+  // pressed — nothing is read back, so the segmented control beside it, bound
+  // to the same message, is what says the publish landed.
+  await page.getByRole("button", { name: "Night" }).click()
+  await expect(boost).toHaveAttribute("aria-pressed", "false")
+
   // The latching button names its state; two presses are a round trip.
   const lamp = page.getByRole("button", { name: "Lamp" })
   await expect(lamp).toHaveText("Off")