fix(settings): label first-year period as "Första räkenskapsåret" (#422)

The FiscalPeriodEditor section is for adjusting the onboarding fiscal
year and always loads the oldest period. After a multi-year SIE import
the oldest period is no longer the company's current year, so the
"Nuvarande period:" label misled at least one user into thinking their
data had landed in the wrong year. Rename to match the section header.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

components/settings/FiscalPeriodEditor.tsx

@@ -288,7 +288,7 @@ function BlockedState({
       </div>
       <div className="text-sm text-muted-foreground space-y-1">
         <p>
-          Nuvarande period:{' '}
+          Första räkenskapsåret:{' '}
           <span className="font-medium text-foreground">
             {formatSwedishDate(period.period_start)} &ndash; {formatSwedishDate(period.period_end)}
           </span>