ci: run the web UI DOM test suites; fix two stale suites (#660)

A new "Web UI JS tests" job installs jsdom, starts the web interface in
emulator mode and runs test/js/run_all.js with REQUIRE_DOM=1, which makes a
DOM suite that can't run a failure rather than a silent skip. (The unit
suites were already covered through pytest.)

Two suites failed against main when run for real:
- test_tools_sections rendered the Tools partial without LEDEscape, which
  base.html's app-early.js defines; it now installs it in beforeParse, and
  supplies two sample Starlark apps (one id with a quote) when the server
  has none, instead of assuming a device with apps and Pixlet.
- test_store_dom assumed the live registry had at most 48 plugins; it now
  checks pagination whichever side of 48 it is.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

test/js/dom/test_store_dom.js

@@ -1,5 +1,5 @@
 // Real-DOM (jsdom) test of the migrated Plugin Store toolbar, against the
-// server's actual 48-plugin registry — enough data for 4 pages, so pagination,
+// server's actual plugin registry (48+ plugins) — enough data for 4 pages, so pagination,
 // the ellipsis strip and per-page changes are exercised for real.
 // The card renderer itself is stubbed: Step 2 did not touch it, and stubbing
 // keeps the assertions on the parts that did change.
@@ -119,7 +119,12 @@ function slice(src, a, b) {
   // ── per-page ───────────────────────────────────────────────────────────
   change($('store-per-page'), '48');
   ok('per-page 48 shows all in one page', cards() === Math.min(48, N), cards());
-  ok('pagination hidden when one page', pagTop().trim() === '' || pageBtns().length === 0, pagTop().slice(0, 80));
+  // The live registry outgrew 48 plugins, so check whichever case it is.
+  if (N <= 48) {
+    ok('pagination hidden when one page', pagTop().trim() === '' || pageBtns().length === 0, pagTop().slice(0, 80));
+  } else {
+    ok('pagination still shown when 48 per page leaves more', pageBtns().length > 0, pagTop().slice(0, 80));
+  }
   ok('per-page persisted', window.localStorage.getItem('storePerPage') === '48');
   change($('store-per-page'), '12');
   ok('back to 12 restores pagination', cards() === 12 && pageBtns().length > 0);

test/js/dom/test_tools_sections.js

@@ -12,6 +12,19 @@ const get = p => new Promise((res, rej) =>
   const partial = await get('/partials/tools');
   const bridge = JSON.parse(await get('/api/v3/integrations/mqtt-bridge'));
   const apps = JSON.parse(await get('/api/v3/starlark/editor/apps'));
+  // A dev box or CI runner has no Starlark apps and no Pixlet binary, which
+  // leaves the editor section with nothing to render. Keep the real payload's
+  // shape but give it two apps -- one id carrying a quote, which is what the
+  // dataset (not inline onclick) check below exists to catch.
+  if (!(apps.data && apps.data.apps && apps.data.apps.length)) {
+    apps.data = Object.assign({}, apps.data, {
+      pixlet_available: true,
+      apps: [
+        { id: 'clock-demo', name: 'Clock demo', editable: true },
+        { id: "it's-quoted", name: 'Quoted id', editable: true },
+      ],
+    });
+  }
 
   const errs = [];
   const vc = new VirtualConsole();
@@ -37,7 +50,13 @@ const get = p => new Promise((res, rej) =>
   // and the page fails in ways it never would in a browser.
   const dom = new JSDOM(`<!doctype html><html><body>${partial}</body></html>`,
     { runScripts: 'dangerously', virtualConsole: vc, url: BASE + '/',
-      beforeParse(w) { w.fetch = stubFetch; w.confirm = () => true; } });
+      beforeParse(w) {
+        w.fetch = stubFetch; w.confirm = () => true;
+        // The partial runs inside base.html, which defines LEDEscape (in
+        // app-early.js) before any tab loads; rendered on its own it needs it
+        // installed the same way.
+        require('../led_escape').install(w);
+      } });
   const { window } = dom;
 
   const tick = ms => new Promise(r => setTimeout(r, ms));