ci: supply throwaway JWT/SESSION secrets for E2E (NODE_ENV=production)

pnpm test:e2e runs via react-router serve which boots with
NODE_ENV=production; the new requireSecret() guard refuses to start
without explicit values. CI now supplies CI-only throwaway secrets so
the guard still bites in real prod deploys without breaking the test
job.

.github/workflows/ci.yml

@@ -257,6 +257,12 @@ jobs:
           BROUTER_URL: http://localhost:17777
           E2E: "true"
           INTEGRATION_SECRET: ${{ secrets.INTEGRATION_SECRET }}
+          # pnpm test:e2e starts the server via `react-router serve`, which
+          # boots with NODE_ENV=production. requireSecret() refuses to start
+          # in production without these set — supply random throwaway values
+          # for CI so the fail-loud guard still bites in real prod deploys.
+          JWT_SECRET: ci-jwt-secret-only-for-e2e-do-not-reuse
+          SESSION_SECRET: ci-session-secret-only-for-e2e-do-not-reuse
 
       - name: Playwright job summary
         if: ${{ !cancelled() }}