test: gate progressive dock browser journey

tests/e2e/test_progressive_mobile_dock_release.py

@@ -1,6 +1,11 @@
+import os
 from pathlib import Path
 
 import pytest
+
+if os.getenv("STACKCHAIN_RUN_RELEASE_E2E") != "1":
+    pytest.skip("progressive mobile dock checks run only in the browser gate", allow_module_level=True)
+pytest.importorskip("playwright.sync_api")
 from playwright.sync_api import expect, sync_playwright