Add list/table view for sessions panel alongside tiles view

- Toggle buttons (Tiles/List) in sessions header, preference
  persisted in localStorage
- List view: table with Name, Date, Duration, Messages, Mode, Actions
  columns; same fields and buttons as tiles, just tabular layout
- Refactored loadSessions() into buildGridHTML/buildListHTML helpers
  with shared attachSessionListeners() for both views
- i18n: Tiles, List, Name, Date, Duration, Messages, Mode, Actions
  keys added to LANG_RU
- Bump 1.22.6, SW cache v37->v38

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__, '1.22.5')
+        self.assertEqual(__version__, '1.22.6')
 
     def test_status_includes_version(self):
         import os