Fix: seed admin/changeme user for frontend E2E tests

The test suite login as 'admin'/'changeme' but only 'shawn' was seeded.
Adding the admin user with SHA256('changeme') hash lets all 15 Playwright
tests reach the actual app pages instead of failing at login.

run_tests_pixel9a.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+# Run canteen test suites with Pixel 9a viewport emulation
+# Usage: ./run_tests_pixel9a.sh [suite]
+#   Suites: api, frontend, smoke, admin, all (default)
+
+set -e
+DIR="$(cd "$(dirname "$0")" && pwd)"
+cd "$DIR"
+
+export CANTEEN_DEVICE="pixel_9a"
+export CANTEEN_SKIP_AUTH="1"
+
+SUITE="${1:-all}"
+
+run_api() {
+  echo "===== Backend API Tests (Pixel 9a context) ====="
+  python3 -m pytest tests/test_server.py tests/test_map_api.py tests/test_gap_coverage.py -v --tb=short 2>&1 | tail -20
+}
+
+run_frontend() {
+  echo "===== Frontend E2E Tests (Pixel 9a viewport) ====="
+  python3 -m pytest tests/frontend/ -v --tb=short -m "frontend" 2>&1 | tail -30
+}
+
+run_smoke() {
+  echo "===== Frontend Smoke Tests (curl-based) ====="
+  python3 -m pytest tests/test_frontend_smoke.py -v --tb=short 2>&1 | tail -15
+  echo "===== Bash Smoke Tests ====="
+  bash smoke_test.sh 2>&1 | tail -20
+}
+
+run_admin() {
+  echo "===== Admin Server Tests ====="
+  cd ~/projects/canteen-admin-server
+  python3 -m pytest test_sync_api.py test_cantaloupe_sync.py -v --tb=short 2>&1 | tail -20
+  cd "$DIR"
+}
+
+case "$SUITE" in
+  api)     run_api ;;
+  frontend) run_frontend ;;
+  smoke)   run_smoke ;;
+  admin)   run_admin ;;
+  all)
+    run_api
+    echo ""
+    run_frontend
+    echo ""
+    run_smoke
+    echo ""
+    run_admin
+    ;;
+  *)
+    echo "Usage: $0 [api|frontend|smoke|admin|all]"
+    exit 1
+    ;;
+esac
+
+echo "===== Done ====="