Wire history button and audit sidebar into WorkSheet

[duchacekjan]

Description

Add a history icon button to every day row in WorkSheet.tsx and mount WorkEntryAuditSidebar. Blocked by #5 (TS contracts and hook) and #6 (WorkEntryAuditSidebar component must exist first).

Changes in src/uck26-frontend/src/features/work/WorkSheet.tsx:

1. Add imports:

   import { History } from 'lucide-react';
   import { WorkEntryAuditSidebar } from './WorkEntryAuditSidebar';

2. Add state: const [auditDate, setAuditDate] = useState<string | null>(null)
3. Add extra <TableHead /> as last column header (no label)
4. In each day <TableRow>, add last <TableCell>:

   <TableCell>
     <IconButton
       variant="ghost"
       size="mini"
       aria-label={`Show history for ${day.label}`}
       data-test-id={`work-history-${day.date}`}
       onClick={() => setAuditDate(prev => prev === day.date ? null : day.date)}
     >
       <History className={auditDate === day.date ? 'text-blue-500' : undefined} />
     </IconButton>
   </TableCell>

5. Add extra <TableCell /> to the summary row to keep column count aligned
6. Mount sidebar at bottom of return (outside table):

   <WorkEntryAuditSidebar
     open={auditDate !== null}
     date={auditDate}
     dateLabel={days.find(d => d.date === auditDate)?.label ?? ''}
     userId={worksheetUserId}
     year={year}
     month={month}
     onClose={() => setAuditDate(null)}
   />

Acceptance Criteria

• Test coverage — add Playwright UI tests in src/UCK26.Ui.Tests/WorkPageTests.cs. Auth via POST /api/auth/login + JWT injected into localStorage. Locate all elements via data-test-id only. Required cases:
  • Click data-test-id="work-history-{date}" for day A, then click for day B → assert sidebar header shows day B's label
  • Click same data-test-id="work-history-{date}" button again → assert data-test-id="work-history-sidebar" is no longer visible
  • Assert history button exists on a weekend row (confirm weekends not excluded)
• Update README.md — no README changes needed; no new commands or setup steps introduced. State: N/A — wiring is an internal component change.
• Update CLAUDE.md — add data-test-id entries for work-history-{date} button and work-history-sidebar to the Testing conventions section (or a new data-test-id reference table if one exists).
• History button present on every day row (including weekends)
• Clicking a button opens sidebar for that date; clicking same button again closes it
• Clicking a different date switches sidebar content
• Active row button highlighted (blue icon)
• Summary row column count remains correct
• data-test-id={work-history-{date}} attribute present on each button
• TypeScript strict mode passes (npm run lint)