STATUS list entries: suppress raw hex when empty, describe FCP data

- decode.py: _build_summary emits 'Data: N bytes — FCP of <file> (...)' for
  STATUS responses with data (FCP already decoded into decoded.response);
  _fcp_brief builds the 'FCP of MF (DF or ADF)' / 'FCP of EF_xxx (...)'
  fragment
- index.html: cmd_description suppresses the raw-hex fallback for
  body-less STATUS rows (nothing to describe beyond type + SW)
- tests: no-data STATUS summary None; DF/EF FCP summaries; pluralization
- Bump 1.22.19, SW cache v50->v51

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__, '1.22.18')
+        self.assertEqual(__version__, '1.22.19')
 
     def test_status_includes_version(self):
         import os