feat: Práce mimo směnu column + right-click menu on PMS cells

- Added PMS summary column after each month's last day
- Merged header cell with rotated "Práce mimo směnu" label spanning
  DEN through D8 rows (no internal borders, overflow hidden)
- PMS cells in person rows are editable (click/double-click)
- Right-click context menu works on PMS cells (value, color, comments)
- PMS values stored as negative month keys in person data
- Dynamic height adjustment when info rows toggled

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/src/App.tsx

@@ -417,7 +417,16 @@ function ScheduleApp({ fileId, fileName, data, compareFileId, onBack, onFileName
     await exportMonthPdf(month, year, data.dayIndex, people, tunnelClosures, tunnelColors)
   }, [data.dayIndex, people, tunnelClosures, tunnelColors])
 
-  const contextDayInfo = contextMenu ? data.dayIndex.find(d => d.idx === contextMenu.dayIdx) : null
+  const MONTH_NAMES_FULL: Record<number, string> = {
+    1:'Leden',2:'Únor',3:'Březen',4:'Duben',5:'Květen',6:'Červen',
+    7:'Červenec',8:'Srpen',9:'Září',10:'Říjen',11:'Listopad',12:'Prosinec',
+  }
+  const contextDayInfo = contextMenu
+    ? contextMenu.dayIdx < 0
+      // PMS cell — synthetic day info
+      ? { idx: contextMenu.dayIdx, day: 0, month: -contextMenu.dayIdx, year: 2026, week: 0, weekend: false } as import('./types').DayInfo
+      : data.dayIndex.find(d => d.idx === contextMenu.dayIdx) ?? null
+    : null
   const contextPerson = contextMenu?.personId ? people.find(p => p.id === contextMenu.personId) : null
   const contextCellData = contextMenu?.personId
     ? people.find(p => p.id === contextMenu.personId)?.data[String(contextMenu.dayIdx)]