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/app/admin/_components/FormField.tsx

@@ -0,0 +1,171 @@
+interface InputFieldProps {
+  label: string;
+  value: string;
+  onChange: (value: string) => void;
+  placeholder?: string;
+  type?: "text" | "url" | "tel";
+}
+
+export function InputField({
+  label,
+  value,
+  onChange,
+  placeholder,
+  type = "text",
+}: InputFieldProps) {
+  return (
+    <div>
+      <label className="block text-sm text-neutral-400 mb-1.5">{label}</label>
+      <input
+        type={type}
+        value={value}
+        onChange={(e) => onChange(e.target.value)}
+        placeholder={placeholder}
+        className="w-full rounded-lg border border-white/10 bg-neutral-800 px-4 py-2.5 text-white placeholder-neutral-500 outline-none focus:border-gold transition-colors"
+      />
+    </div>
+  );
+}
+
+interface TextareaFieldProps {
+  label: string;
+  value: string;
+  onChange: (value: string) => void;
+  placeholder?: string;
+  rows?: number;
+}
+
+export function TextareaField({
+  label,
+  value,
+  onChange,
+  placeholder,
+  rows = 3,
+}: TextareaFieldProps) {
+  return (
+    <div>
+      <label className="block text-sm text-neutral-400 mb-1.5">{label}</label>
+      <textarea
+        value={value}
+        onChange={(e) => onChange(e.target.value)}
+        placeholder={placeholder}
+        rows={rows}
+        className="w-full rounded-lg border border-white/10 bg-neutral-800 px-4 py-2.5 text-white placeholder-neutral-500 outline-none focus:border-gold transition-colors resize-y"
+      />
+    </div>
+  );
+}
+
+interface SelectFieldProps {
+  label: string;
+  value: string;
+  onChange: (value: string) => void;
+  options: { value: string; label: string }[];
+  placeholder?: string;
+}
+
+export function SelectField({
+  label,
+  value,
+  onChange,
+  options,
+  placeholder,
+}: SelectFieldProps) {
+  return (
+    <div>
+      <label className="block text-sm text-neutral-400 mb-1.5">{label}</label>
+      <select
+        value={value}
+        onChange={(e) => onChange(e.target.value)}
+        className="w-full rounded-lg border border-white/10 bg-neutral-800 px-4 py-2.5 text-white outline-none focus:border-gold transition-colors"
+      >
+        {placeholder && (
+          <option value="" disabled>
+            {placeholder}
+          </option>
+        )}
+        {options.map((opt) => (
+          <option key={opt.value} value={opt.value}>
+            {opt.label}
+          </option>
+        ))}
+      </select>
+    </div>
+  );
+}
+
+interface TimeRangeFieldProps {
+  label: string;
+  value: string;
+  onChange: (value: string) => void;
+  onBlur?: () => void;
+}
+
+export function TimeRangeField({ label, value, onChange, onBlur }: TimeRangeFieldProps) {
+  // Parse "HH:MM–HH:MM" into start and end
+  const parts = value.split("–");
+  const start = parts[0]?.trim() || "";
+  const end = parts[1]?.trim() || "";
+
+  function update(s: string, e: string) {
+    if (s && e) {
+      onChange(`${s}–${e}`);
+    } else if (s) {
+      onChange(s);
+    } else {
+      onChange("");
+    }
+  }
+
+  return (
+    <div>
+      <label className="block text-sm text-neutral-400 mb-1.5">{label}</label>
+      <div className="flex items-center gap-2">
+        <input
+          type="time"
+          value={start}
+          onChange={(e) => update(e.target.value, end)}
+          onBlur={onBlur}
+          className="flex-1 rounded-lg border border-white/10 bg-neutral-800 px-3 py-2.5 text-white outline-none focus:border-gold transition-colors"
+        />
+        <span className="text-neutral-500">–</span>
+        <input
+          type="time"
+          value={end}
+          onChange={(e) => update(start, e.target.value)}
+          onBlur={onBlur}
+          className="flex-1 rounded-lg border border-white/10 bg-neutral-800 px-3 py-2.5 text-white outline-none focus:border-gold transition-colors"
+        />
+      </div>
+    </div>
+  );
+}
+
+interface ToggleFieldProps {
+  label: string;
+  checked: boolean;
+  onChange: (checked: boolean) => void;
+}
+
+export function ToggleField({ label, checked, onChange }: ToggleFieldProps) {
+  return (
+    <label className="flex items-center gap-2 cursor-pointer">
+      <button
+        type="button"
+        role="switch"
+        aria-checked={checked}
+        onClick={() => onChange(!checked)}
+        className={`relative h-6 w-11 rounded-full transition-colors ${
+          checked ? "bg-gold" : "bg-neutral-700"
+        }`}
+      >
+        <span
+          className={`absolute top-0.5 left-0.5 h-5 w-5 rounded-full bg-white transition-transform ${
+            checked ? "translate-x-5" : ""
+          }`}
+        />
+      </button>
+      <span className="text-sm text-neutral-300">{label}</span>
+    </label>
+  );
+}