fix(e2e): repair failing suite — a11y fixes and stale assertions

Three product a11y defects: drop role="radiogroup" from the /join PWYC
<ul> (it stripped the list role; native radios already group), use
--parch-text on the active contribution chip (was --text-bright, 1.17:1
on --parch), and label the New tag pool USelect on event create.

Three stale tests: real event-type filter labels, updated location
placeholder, and click the label instead of the hidden 0×0 radio.

e2e/admin-events.spec.js

@@ -88,7 +88,7 @@ test.describe('Admin events CRUD', () => {
       .fill('e2e test event description')
 
     await adminPage
-      .getByPlaceholder('e.g., https://zoom.us/j/123... or #channel-name')
+      .getByPlaceholder('e.g., https://zoom.us/j/123..., #channel-name, or TBD')
       .fill('https://example.com/zoom')
 
     const startInput = adminPage.getByPlaceholder(