Files view: the row jump no longer scrolls to the end of the trace (v2.6.1)

- jumpToMessage() rendered the APDU list through the unqualified
  renderMessages(), whose tail pins the view to the bottom (the live-capture
  stick), and only then let focusMessage() smooth-scroll back up to the
  clicked record — the visible jump-to-end-then-back.  It now renders with
  skipScroll, so the only scroll is the focus itself
- the content-follow became conditional: shouldStickToBottom() pins the view
  to the newest messages only while the reader is already at the bottom
  (40 px slack), so the 500 ms live poll no longer pulls away a view the
  reader scrolled to — a Files/map jump is no longer yanked down by the next
  batch.  A freshly opened session or a new capture still lands at the
  bottom (renderMessages(false, true))
- tests (node): the jump's paging/render(true)/focus sequence with stubs, the
  no-session no-op, the stick decision (at bottom / within slack / scrolled
  up / explicit jump / forced / first render) and source pins for
  renderMessages, jumpToMessage, loadSession and startCapture; 527 Python +
  53 Node tests
- README/README_RUS note the follow behaviour; PWA_VERSION/pyproject/
  version.py 2.6.1, SW cache simtrace-analyser-v73

frontend/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'simtrace-analyser-v72';
+const CACHE = 'simtrace-analyser-v73';
 
 const PRECACHE = [
     'index.html',