feat: admin panel with SQLite, auth, and calendar-style schedule editor

Complete admin panel for content management:
- SQLite database with better-sqlite3, seed script from content.ts
- Simple password auth with HMAC-signed cookies (Edge + Node compatible)
- 9 section editors: meta, hero, about, team, classes, schedule, pricing, FAQ, contact
- Team CRUD with image upload and drag reorder
- Schedule editor with Google Calendar-style visual timeline (colored blocks, overlap detection, click-to-add)
- All public components refactored to accept data props from DB (with fallback to static content)
- Middleware protecting /admin/* and /api/admin/* routes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/sections/Classes.tsx

@@ -2,12 +2,11 @@
 
 import Image from "next/image";
 import { Flame, Sparkles, Wind, Zap, Star, Monitor } from "lucide-react";
-import { siteContent } from "@/data/content";
 import { SectionHeading } from "@/components/ui/SectionHeading";
 import { Reveal } from "@/components/ui/Reveal";
 import { ShowcaseLayout } from "@/components/ui/ShowcaseLayout";
 import { useShowcaseRotation } from "@/hooks/useShowcaseRotation";
-import type { ClassItem } from "@/types";
+import type { ClassItem, SiteContent } from "@/types";
 import { UI_CONFIG } from "@/lib/config";
 
 const iconMap: Record<string, React.ReactNode> = {
@@ -19,8 +18,11 @@ const iconMap: Record<string, React.ReactNode> = {
   monitor: <Monitor size={20} />,
 };
 
-export function Classes() {
-  const { classes } = siteContent;
+interface ClassesProps {
+  data: SiteContent["classes"];
+}
+
+export function Classes({ data: classes }: ClassesProps) {
   const { activeIndex, select, setHovering } = useShowcaseRotation({
     totalItems: classes.items.length,
     autoPlayInterval: UI_CONFIG.showcase.autoPlayInterval,