Make Stop Capture button red and prominent

- Add --danger/--danger-hover CSS variables (dark + light themes)
- .stop button now uses red background + white text with brighter hover
  (was muted gray, easy to miss)
- Bump 1.22.3, SW cache v34->v35

tests/test_pcap_import.py

@@ -224,7 +224,7 @@ class TestImportEndpoint(unittest.TestCase):
 class TestVersion(unittest.TestCase):
     def test_package_version(self):
         from simtrace2_pysniff import __version__
-        self.assertEqual(__version__, '1.22.2')
+        self.assertEqual(__version__, '1.22.3')
 
     def test_status_includes_version(self):
         import os