The refresh button turns while its feed is checked (#78)

The feed events already put a spinner on the sidebar row, which a phone
hides. The same state now sets scan-this (the open feed, or a feed in the
open folder) and scan-any (any of your feeds) on <body>, and the refresh
icons turn under them. On <body> because the feed page is redrawn as items
come in.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/ui/app.spec.js

@@ -1443,3 +1443,20 @@ test('Share hands the feed, the item and the file to the share sheet', async ({
     { title: 'Second Episode', url: expect.stringContaining('/ep1.mp3?2') },
   ]);
 });
+
+test('a refresh button turns while what it checks is being checked', async ({ page }) => {
+  await page.locator('.feed', { hasText: 'Test Show' }).click();
+  const spin = sel => page.locator(sel).evaluate(el => getComputedStyle(el).animationName);
+  const btn = '.fhead [data-a=scan] .i';
+  await expect(page.locator(btn)).toBeVisible();
+  expect(await spin(btn)).toBe('none');
+  await page.evaluate(() => setScanning('test-show', true));
+  expect(await spin(btn)).toBe('ipxspin');
+  expect(await spin('#scanAll .i')).toBe('ipxspin');
+  // Another feed being checked turns the toolbar's, not this page's.
+  await page.evaluate(() => { setScanning('test-show', false); setScanning('multi-show', true); });
+  expect(await spin(btn)).toBe('none');
+  expect(await spin('#scanAll .i')).toBe('ipxspin');
+  await page.evaluate(() => setScanning('multi-show', false));
+  expect(await spin('#scanAll .i')).toBe('none');
+});