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/ClassEditors.tsx

@@ -32,7 +32,7 @@ export function ClassMaxHoursDayEditor() {
     <ConstraintShell
       testId="class-max-hours-day-editor"
       title="Klasse: Max. Stunden / Tag"
-      description="Beispiel: „5a hoechstens 6 Stunden pro Tag" (jugendgerecht)."
+      description={"Beispiel: „5a hoechstens 6 Stunden pro Tag" (jugendgerecht)."}
       newLabel="+ Neue Regel"
       newDisabled={classes.length === 0}
       prereqWarning={classes.length === 0 ? 'Zuerst Klassen anlegen.' : null}
@@ -95,7 +95,7 @@ export function ClassNoGapsEditor() {
     <ConstraintShell
       testId="class-no-gaps-editor"
       title="Klasse: Keine Freistunden"
-      description="Soft-Regel: Klasse soll keine Loecher zwischen Lessons haben."
+      description={"Soft-Regel: Klasse soll keine Loecher zwischen Lessons haben."}
       newLabel="+ Neue Regel"
       newDisabled={classes.length === 0}
       prereqWarning={classes.length === 0 ? 'Zuerst Klassen anlegen.' : null}