test(e2e): bump EVENT_DETAILS priority + mock /prices in trending (MMQA-1800)

Two more endpoints surfaced on the previous CI run:

- POLYMARKET_EVENT_DETAILS_MOCKS lacked an explicit priority. Tied at
  default priority with the proxy fallback handler in MockServerE2E,
  the wildcard *.polymarket.com allowlist had been hiding cases where
  the fallback won. Bump to PRIORITY.BASE so events/{id} interception
  is reliable. Fixes events/60362 (predict-claim-positions) and
  events/79682 (predict-open-position).

- trending-api-mocks: add a POST /clob.polymarket.com/prices mock
  returning {} so the prediction detail render in trending-feed.spec
  doesn't leak.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: chrisleewilcox

tests/api-mocking/mock-responses/polymarket/polymarket-mocks.ts

@@ -213,6 +213,7 @@ export const POLYMARKET_EVENT_DETAILS_MOCKS = async (mockServer: Mockttp) => {
       const url = new URL(request.url).searchParams.get('url');
       return Boolean(url?.includes('gamma-api.polymarket.com/events/'));
     })
+    .asPriority(PRIORITY.BASE)
     .thenCallback((request) => {
       const url = new URL(request.url).searchParams.get('url');
       const eventIdMatch = url?.match(/\/events\/([0-9]+)$/);

tests/api-mocking/mock-responses/trending-api-mocks.ts

@@ -303,5 +303,13 @@ export const TRENDING_API_MOCKS: MockEventsObject = {
       },
       priority: 1000,
     },
+    {
+      // CLOB prices fetched on prediction detail render. Empty object is
+      // safe for trending-feed which only renders the prediction row.
+      urlEndpoint: /https:\/\/clob\.polymarket\.com\/prices.*/,
+      responseCode: 200,
+      response: {},
+      priority: 1000,
+    },
   ],
 };