Add Files to Discover entry flow E2E tests

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cypress/support/intercept.js

@@ -59,6 +59,12 @@ export function setupApiIntercepts() {
     body: { success: true },
   }).as('deleteUserRole');
 
+  // Filter detail (for fetchFunnel when entering filter from Files)
+  cy.intercept('GET', /\/api\/filters\/\d+$/, {
+    statusCode: 200,
+    body: { rules: [], log: { id: 1 }, name: 'filtered-sample' },
+  }).as('getFilterDetail');
+
   // Discover (map data)
   cy.intercept('GET', '/api/logs/*/discover', {
     fixture: 'api/discover.json',