Topbar: title trim, shorter search, the view selector pinned above the panel (v2.6.3)

- the header title drops its "UICC" prefix — "GSMTAP trace analyser" is enough
- the trace topbar's search input is half its previous width (flex basis
  33.333% -> 16.667%); the session name now ellipsizes instead of wrapping
  the tighter row
- the side-panel view selector moved out of the scrollable side panel into
  the trace topbar: right-aligned over the panel at the panel's width
  (--side-panel-w: 260px, the negative right margin cancelling the topbar's
  16px padding so the edges line up), so it stays visible at all times while
  the panel scrolls
- tests: the topbar/selector position pins (the Files-view wiring test and
  style.test.js), the shared width variable, the halved search basis and the
  title; 527 Python + 61 Node tests
- README/README_RUS: the selector's new place; PWA_VERSION/pyproject/
  version.py 2.6.3, SW cache simtrace-analyser-v77

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__, '2.6.2')
+        self.assertEqual(__version__, '2.6.3')
 
     def test_status_includes_version(self):
         import os