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

frontend/tests/comprion.test.js

@@ -324,8 +324,14 @@ test('Files view: the hex image respects the row limit', () => {
 	assert.equal(view.end, 64);
 });
 
-test('Files view: side-panel dropdown and the timeline are wired', () => {
+test('Files view: the view selector (topbar) and the timeline are wired', () => {
 	assert.match(src, /<select class="side-view-select" id="side-view-select"[^>]*>/);
+	// The selector is a topbar control (before the two-column trace area), so
+	// it stays visible while the side panel scrolls.
+	const topbar = src.indexOf('<div class="trace-topbar">');
+	const sel = src.indexOf('id="side-view-select"');
+	const main = src.indexOf('<div class="trace-main">');
+	assert.ok(topbar >= 0 && topbar < sel && sel < main, 'selector in the topbar');
 	assert.match(src, /<option value="files" data-l10n="Files">/);
 	assert.doesNotMatch(src, /class="side-tab/);
 	assert.match(src, /id="file-view"/);