Fix JSX attribute syntax in constraint editor descriptions

German curly quotes („…") combined with a closing straight " inside
JSX attribute values were terminating the attribute prematurely, e.g.
`description="Beispiel: „X" (jugendgerecht)."` lost everything after
the inner straight quote. Switch all such descriptions to the JSX
expression form `description={"…"}` so the inner quotes are part of
a JavaScript string literal and parsed correctly.

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

studio-v2/app/stundenplan/_components/regeln/TeacherMaxHoursEditors.tsx

@@ -34,7 +34,7 @@ export function TeacherMaxHoursDayEditor() {
     <ConstraintShell
       testId="teacher-max-hours-day-editor"
       title="Lehrer: Max. Stunden / Tag"
-      description="Beispiel: „Anna unterrichtet hoechstens 6 Stunden pro Tag" (oft Soft-Regel)."
+      description={"Beispiel: „Anna unterrichtet hoechstens 6 Stunden pro Tag" (oft Soft-Regel)."}
       newLabel="+ Neue Regel"
       newDisabled={teachers.length === 0}
       prereqWarning={teachers.length === 0 ? 'Zuerst Lehrer anlegen.' : null}
@@ -97,7 +97,7 @@ export function TeacherMaxHoursWeekEditor() {
     <ConstraintShell
       testId="teacher-max-hours-week-editor"
       title="Lehrer: Max. Stunden / Woche"
-      description="Beispiel: Teilzeit 50% → max. 14 h/Woche (harte Regel aus Vertrag)."
+      description={"Beispiel: Teilzeit 50% → max. 14 h/Woche (harte Regel aus Vertrag)."}
       newLabel="+ Neue Regel"
       newDisabled={teachers.length === 0}
       prereqWarning={teachers.length === 0 ? 'Zuerst Lehrer anlegen.' : null}