Files view: the jumped-to record stays selected (v2.6.2)

- focusMessage()/scrollToType() highlighted the target and removed the class
  after 1500 ms, so a Files-row (or map/category) jump looked selected for a
  moment and then lost it; on top of that any re-render (the 500 ms live
  poll, a filter/search change) rebuilt the list and dropped the highlight —
  even for a clicked entry
- the selection is now persistent app state (STATE.selectedIdx): the render
  marks the entry (gap rows included), focusMessage records the index before
  rendering, showDetail records it for plain clicks, scrollToType persists it
  too (clearing the previous highlight), and a new session/capture resets it
  so a stale index cannot mark an unrelated APDU
- tests: a stub-driven focusMessage case (state + detail updated, no render
  and no timer), the filter-clearing case, and source pins for
  renderMessages, focusMessage, scrollToType, showDetail, loadSession and
  startCapture; 527 Python + 58 Node tests
- README/README_RUS: the jump leaves the record selected; PWA_VERSION/
  pyproject/version.py 2.6.2, SW cache simtrace-analyser-v76

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__, '2.6.1')
+        self.assertEqual(__version__, '2.6.2')
 
     def test_status_includes_version(self):
         import os