SUNDIAL solar dial v0.3: round screen, NOAA solar math, day/night arc

- 466px round layout, designWidth 466 (S4 41mm 466x466)
- solar position + dayProgress in src/common/solar.js (pure, TDD'd)
- sunrise/sunset sweep, night moon, countdown, 30s refresh
- tests: solar math, page logic, circle geometry/contrast

tests/marker.cjs

@@ -0,0 +1,32 @@
+// Compatibility contract, NOT a reproduction of the watch's native crash.
+// Marker must use documented numeric positioning, not chained transforms.
+const fs = require('node:fs');
+const vm = require('node:vm');
+const assert = require('node:assert/strict');
+const solar = require('../src/common/solar.js');
+const ux = fs.readFileSync('src/pages/index/index.ux', 'utf8');
+const body = ux.match(/<script>([\s\S]*?)<\/script>/)[1]
+  .replace(/import\s+solar\s+from\s+'[^']*';?/, '')
+  .replace('export default', '');
+const spec = vm.runInNewContext('(' + body + ')', {solar, Date, Math, String, Number});
+const page = Object.assign({}, spec, JSON.parse(JSON.stringify(spec.private)));
+page.onInit();
+page.update();
+assert.ok(page.markerStyle && Number.isFinite(parseFloat(page.markerStyle.left)),
+  'marker must expose a finite left coordinate via a bound style object');
+assert.match(ux, /style="{{\s*markerStyle\s*}}"/);
+assert.doesNotMatch(ux, /transform\s*:/);
+assert.doesNotMatch(ux, /width:\s*0px/);
+const size = Number(ux.match(/\.sunDot\s*\{[^}]*width:\s*(\d+)px/)[1]);
+// Check actual bound marker box, not an unused constant.
+for (let angle = -270; angle <= 90; angle++) {
+  page.sunAngle = angle;
+  page.positionMarker();
+  const x = parseFloat(page.markerStyle.left), y = parseFloat(page.markerStyle.top);
+  assert.ok(Number.isInteger(x) && Number.isInteger(y));
+  for (const dx of [0, size]) for (const dy of [0, size]) {
+    assert.ok(Math.hypot(x + dx - 233, y + dy - 233) <= 200,
+      `marker box leaves the 400px dial at angle ${angle}`);
+  }
+}
+console.log('MARKER PASS: bound coordinates, no transforms, actual box fits all angles');