feat: MC detail popup, image crop editor, empty dates support

Master Classes:
- Detail popup on card click with description, all dates, location+address
- Card shows only first date (or "Скоро" if no dates)
- Trainer name clickable to open bio
- Text backdrop panel on cards for readability
- No photo overlay darkening
- Fix crash when MC has no/empty slots
- Price "BYN" no longer duplicated
- Admin: ImageCropField replaces PhotoPreview (with focal/zoom)
- Admin: RichTextarea for description
- Admin: photo+fields side-by-side layout, fixed photo width

Pricing:
- Added rentalSubtitle field for rental tab info

src/app/page.tsx

@@ -49,7 +49,7 @@ export default function HomePage() {
           {openDayData && content?.popups && <OpenDay data={openDayData} popups={content.popups} teamMembers={content.team?.members ?? []} locations={content.schedule?.locations} />}
           {content?.schedule && <Schedule data={content.schedule} scheduleConfig={content.scheduleConfig} classItems={content.classes?.items ?? []} teamMembers={content.team?.members ?? []} />}
           {content?.pricing && <Pricing data={content.pricing} />}
-          {content?.masterClasses && <MasterClasses data={content.masterClasses} regCounts={mcRegCounts} popups={content.popups} />}
+          {content?.masterClasses && <MasterClasses data={content.masterClasses} regCounts={mcRegCounts} popups={content.popups} locations={content.schedule?.locations} />}
           {content?.news && <News data={content.news} />}
           {content?.faq && <FAQ data={content.faq} />}
           {content?.contact && <Contact data={content.contact} />}