feat(case-ui): full-width tabs + parties popover + subject on title line

Chair-requested refinements to the case banner:
- Tabs now span the full band width via justify-between — wide gaps with the
  current 6 tabs, tightening as more are added (gap-2 no-overlap floor).
- Parties moved out of the always-on header line into a "צדדים" Popover, so the
  band is shorter and the tab content sits higher on the page.
- Case subject (title) moved up onto the case-number line in a smaller font,
  instead of its own line below.

tsc --noEmit + eslint clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/app/cases/[caseNumber]/page.tsx

@@ -80,10 +80,12 @@ export default function CaseDetailPage({
   ];
 
   // V2 "segmented" tab strip (X17): each tab a pill, active = raised white card.
+  // Spread full-width via justify-between (chair request) — wide gaps with few
+  // tabs, tightening as more are added; gap-2 is the no-overlap floor.
   const tabsList = (
     <TabsList
       variant="line"
-      className="!h-auto gap-1.5 p-0 flex-wrap justify-start"
+      className="!h-auto w-full gap-2 p-0 justify-between"
     >
       {tabDefs.map(([value, label, Icon]) => (
         <TabsTrigger