feat: Open Day class duration + max participants, UI fixes

- Class duration: editable end time (was hardcoded +1h), shown as range
- Max participants per class (0 = unlimited), shown as "3/10 чел."
- New DB migration 14: max_participants column on open_day_classes
- Min bookings moved to separate row with hint text
- "Скидка" renamed to "Цена со скидкой" for clarity
- Cancel/recover icon: Ban for cancel, RotateCcw for recover

src/lib/db.ts

@@ -255,6 +255,16 @@ const migrations: Migration[] = [
       }
     },
   },
+  {
+    version: 14,
+    name: "add_max_participants_to_open_day_classes",
+    up: (db) => {
+      const cols = db.prepare("PRAGMA table_info(open_day_classes)").all() as { name: string }[];
+      if (!cols.some((c) => c.name === "max_participants")) {
+        db.exec("ALTER TABLE open_day_classes ADD COLUMN max_participants INTEGER NOT NULL DEFAULT 0");
+      }
+    },
+  },
 ];
 
 function runMigrations(db: Database.Database) {
@@ -975,6 +985,7 @@ interface OpenDayClassRow {
   style: string;
   cancelled: number;
   sort_order: number;
+  max_participants: number;
   booking_count?: number;
 }
 
@@ -988,6 +999,7 @@ export interface OpenDayClass {
   style: string;
   cancelled: boolean;
   sortOrder: number;
+  maxParticipants: number;
   bookingCount: number;
 }
 
@@ -1054,6 +1066,7 @@ function mapClassRow(r: OpenDayClassRow): OpenDayClass {
     style: r.style,
     cancelled: !!r.cancelled,
     sortOrder: r.sort_order,
+    maxParticipants: r.max_participants ?? 0,
     bookingCount: r.booking_count ?? 0,
   };
 }
@@ -1207,7 +1220,7 @@ export function getOpenDayClasses(eventId: number): OpenDayClass[] {
 
 export function updateOpenDayClass(
   id: number,
-  data: Partial<{ hall: string; startTime: string; endTime: string; trainer: string; style: string; cancelled: boolean; sortOrder: number }>
+  data: Partial<{ hall: string; startTime: string; endTime: string; trainer: string; style: string; cancelled: boolean; sortOrder: number; maxParticipants: number }>
 ): void {
   const db = getDb();
   const sets: string[] = [];
@@ -1219,6 +1232,7 @@ export function updateOpenDayClass(
   if (data.style !== undefined) { sets.push("style = ?"); vals.push(data.style); }
   if (data.cancelled !== undefined) { sets.push("cancelled = ?"); vals.push(data.cancelled ? 1 : 0); }
   if (data.sortOrder !== undefined) { sets.push("sort_order = ?"); vals.push(data.sortOrder); }
+  if (data.maxParticipants !== undefined) { sets.push("max_participants = ?"); vals.push(data.maxParticipants); }
   if (sets.length === 0) return;
   vals.push(id);
   db.prepare(`UPDATE open_day_classes SET ${sets.join(", ")} WHERE id = ?`).run(...vals);