feat: harden admin security, add AI trip planner, map view, and SEO/notification improvements

Security:
- requireAdmin() session check added to every admin-only server action
  (previously relied only on middleware path matching, which Next.js
  Server Actions don't reliably respect)
- Real Prisma + bcrypt admin auth, replacing hardcoded credentials; split
  into an Edge-safe auth.config.ts (used by proxy.ts) and the full
  Prisma-backed auth.ts (route handler, server actions, server components)
- Removed hardcoded fallback secret on the Instagram sync cron endpoint
- Honeypot field + per-IP rate limiting on contact/business-submission
  forms and the analytics events endpoint

Features:
- AI trip planner (/plan-olustur, /plan/[id]) backed by DeepSeek, grounded
  to only recommend isLocalApproved listings, with a deterministic
  link-injection fallback for anything the model doesn't format as markdown
- Interactive Leaflet/OpenStreetMap view on category listing pages
- Telegram notifications for new contact messages and business submissions

SEO:
- Brand-consistent favicon/apple-icon/PWA icons and default Open Graph/
  Twitter share images, generated via next/og (replacing default Next.js
  placeholders)
- BreadcrumbList structured data on category and listing detail pages
- Fixed two remaining raw <img> tags to use next/image

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

components/HoneypotField.tsx

@@ -0,0 +1,16 @@
+// Invisible spam trap: real visitors never see or fill this field, so any
+// submission with it filled in is almost certainly a bot. Server actions
+// check `formData.get(HONEYPOT_FIELD_NAME)` and silently no-op if it's set.
+export const HONEYPOT_FIELD_NAME = 'website_url'
+
+export default function HoneypotField() {
+  return (
+    <div
+      aria-hidden="true"
+      style={{ position: 'absolute', left: '-9999px', top: 0, width: 0, height: 0, overflow: 'hidden' }}
+    >
+      <label htmlFor={HONEYPOT_FIELD_NAME}>Website</label>
+      <input type="text" id={HONEYPOT_FIELD_NAME} name={HONEYPOT_FIELD_NAME} tabIndex={-1} autoComplete="off" />
+    </div>
+  )
+}