fix(salary): recompute entitled_days on existing ledger rows and record pre-cutover taken days (#1403)

The vacation ledger sync carried entitled_days verbatim on existing open
rows while re-deriving accrued and taken, so a stale entitled value (for
example the flat 25 stored before Semesterlagen 7 § pro-rating existed)
survived every sync. The recompute loop now re-derives entitled the same
way the lazy-seed path does, with the opening-balance cutover still
outranking recomputation for the year containing cutover_date.

Opening balances could also not record paid vacation days already taken
in the cutover year under the previous payroll system. New additive
column employee_opening_balances.vacation_days_taken_this_year (NUMERIC
NOT NULL DEFAULT 0, CHECK 0..40) threaded through the shared service,
the Zod schema, the MCP staging tool (schema + mergeable fields), the
staged-operation executor, the v1 REST routes, and the employee editor
form. Ledger semantics for the cutover year, on both seed and recompute
paths: entitled = remaining + taken_this_year, taken = booked-run taken
+ taken_this_year, so remaining keeps meaning remaining and the seeded
value survives every subsequent sync.

Fixes #1347

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

components/salary/OpeningBalancesPanel.tsx

@@ -27,6 +27,7 @@ interface OpeningBalancesData {
   ytd_tax: number
   ytd_net: number
   vacation_paid_days_remaining: number
+  vacation_days_taken_this_year: number
   vacation_saved_days_by_year: Record<string, number>
   opening_semester_liability: number
   opening_semester_liability_avgifter: number
@@ -52,6 +53,7 @@ export function OpeningBalancesPanel({ employeeId, canWrite }: { employeeId: str
   const [ytdTax, setYtdTax] = useState('')
   const [ytdNet, setYtdNet] = useState('')
   const [daysRemaining, setDaysRemaining] = useState('')
+  const [daysTaken, setDaysTaken] = useState('')
   const [savedByYear, setSavedByYear] = useState<Record<string, string>>({})
   const [liability, setLiability] = useState('')
   const [liabilityAvgifter, setLiabilityAvgifter] = useState('')
@@ -71,6 +73,7 @@ export function OpeningBalancesPanel({ employeeId, canWrite }: { employeeId: str
           setYtdTax(String(data.ytd_tax))
           setYtdNet(String(data.ytd_net))
           setDaysRemaining(String(data.vacation_paid_days_remaining))
+          setDaysTaken(String(data.vacation_days_taken_this_year ?? 0))
           setSavedByYear(
             Object.fromEntries(
               Object.entries(data.vacation_saved_days_by_year ?? {}).map(([y, d]) => [y, String(d)]),
@@ -103,6 +106,7 @@ export function OpeningBalancesPanel({ employeeId, canWrite }: { employeeId: str
         ytd_tax: parseFloat(ytdTax) || 0,
         ytd_net: parseFloat(ytdNet) || 0,
         vacation_paid_days_remaining: parseFloat(daysRemaining) || 0,
+        vacation_days_taken_this_year: parseFloat(daysTaken) || 0,
         vacation_saved_days_by_year: saved,
         opening_semester_liability: parseFloat(liability) || 0,
         opening_semester_liability_avgifter: parseFloat(liabilityAvgifter) || 0,
@@ -215,6 +219,12 @@ export function OpeningBalancesPanel({ employeeId, canWrite }: { employeeId: str
               <Input id="ob-days-remaining" type="number" min={0} max={40} step={0.5} value={daysRemaining}
                 onChange={(e) => setDaysRemaining(e.target.value)} disabled={readOnly} className="tabular-nums" />
             </div>
+            <div className="space-y-2">
+              <Label htmlFor="ob-days-taken">{t('opening_balances_days_taken')}</Label>
+              <Input id="ob-days-taken" type="number" min={0} max={40} step={0.5} value={daysTaken}
+                onChange={(e) => setDaysTaken(e.target.value)} disabled={readOnly} className="tabular-nums" />
+              <p className="text-xs text-muted-foreground">{t('opening_balances_days_taken_hint')}</p>
+            </div>
             <div className="space-y-2">
               <Label htmlFor="ob-liability">{t('opening_balances_liability')}</Label>
               <Input id="ob-liability" type="number" min={0} value={liability}