feat: min/max participants — shared ParticipantLimits component

- New ParticipantLimits component in FormField.tsx (reusable)
- Used in both Open Day settings and MC editor — identical layout
- Open Day: event-level min/max (DB migration 15)
- MC: per-event min/max (JSON fields)
- Public: waiting list when full, spots counter, amber success modal

src/app/page.tsx

@@ -15,10 +15,15 @@ import { Footer } from "@/components/layout/Footer";
 import { getContent } from "@/lib/content";
 import { OpenDay } from "@/components/sections/OpenDay";
 import { getActiveOpenDay } from "@/lib/openDay";
+import { getAllMcRegistrations } from "@/lib/db";
 
 export default function HomePage() {
   const content = getContent();
   const openDayData = getActiveOpenDay();
+  // Count MC registrations per title for capacity check
+  const allMcRegs = getAllMcRegistrations();
+  const mcRegCounts: Record<string, number> = {};
+  for (const reg of allMcRegs) mcRegCounts[reg.masterClassTitle] = (mcRegCounts[reg.masterClassTitle] || 0) + 1;
 
   return (
     <>
@@ -36,7 +41,7 @@ export default function HomePage() {
         />
         <Team data={content.team} schedule={content.schedule.locations} />
         <Classes data={content.classes} />
-        <MasterClasses data={content.masterClasses} />
+        <MasterClasses data={content.masterClasses} regCounts={mcRegCounts} />
         <Schedule data={content.schedule} classItems={content.classes.items} />
         <Pricing data={content.pricing} />
         <News data={content.news} />