Enrich per-event RST/VCC labels (ATR STARTS / power-up) + decode server-side

- decode_line_event adds human label: RST de-asserted->ATR STARTS,
  VCC applied->VCC ON (power-up); keep canonical event string
- Enable rst/vcc in DB decode dispatch so PWA receives decoded
  (fixes bare RESET/VCC fallback and a latent showDetail crash)
- PWA line_event_label/showDetail render decoded.label
- Bump 1.22.1, SW cache v32->v33; +1 test

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__, '1.22.0')
+        self.assertEqual(__version__, '1.22.1')
 
     def test_status_includes_version(self):
         import os