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.

tests/frontend/conftest.py

@@ -51,6 +51,35 @@ sys.path.insert(0, str(PROJECT_ROOT))
 # Global env: skip auth for all tests
 os.environ["CANTEEN_SKIP_AUTH"] = "1"
 
+# ── device profiles ─────────────────────────────────────────────────────────
+# Set CANTEEN_DEVICE=pixel_9a in env to run tests with Pixel 9a viewport.
+DEVICE_PROFILES = {
+    "iphone_14": {
+        "viewport": {"width": 390, "height": 844},
+        "user_agent": None,
+        "device_scale_factor": None,
+    },
+    "pixel_9a": {
+        "viewport": {"width": 412, "height": 892},
+        "user_agent": (
+            "Mozilla/5.0 (Linux; Android 15; Pixel 9a) "
+            "AppleWebKit/537.36 (KHTML, like Gecko) "
+            "Chrome/130.0.6723.58 Mobile Safari/537.36"
+        ),
+        "device_scale_factor": 2.625,
+    },
+}
+
+
+def get_device_config() -> tuple:
+    """Return device config dict + name based on CANTEEN_DEVICE env var."""
+    device = os.environ.get("CANTEEN_DEVICE", "iphone_14").lower().replace("-", "_")
+    if device in DEVICE_PROFILES:
+        return DEVICE_PROFILES[device], device
+    print(f"⚠ Unknown device '{device}', falling back to iphone_14")
+    return DEVICE_PROFILES["iphone_14"], "iphone_14"
+
+
 # ── helpers ────────────────────────────────────────────────────────────────
 
 
@@ -143,10 +172,15 @@ def live_server(test_db_path):
 def page(browser, live_server):
     """Create a Playwright page pointed at the live server.
 
-    iPhone 14 viewport, Orlando FL geolocation, geolocation permission granted.
+    Mobile viewport driven by CANTEEN_DEVICE env var (default: iphone_14).
+    Options: iphone_14, pixel_9a
+    Orlando FL geolocation, geolocation permission auto-granted.
     """
+    device_config, device_name = get_device_config()
     context = browser.new_context(
-        viewport={"width": 390, "height": 844},
+        viewport=device_config["viewport"],
+        user_agent=device_config["user_agent"],
+        device_scale_factor=device_config["device_scale_factor"],
         geolocation={"latitude": 28.3852, "longitude": -81.5639},
         permissions=["geolocation"],
     )