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>

public/manifest.json

@@ -9,14 +9,14 @@
   "orientation": "portrait",
   "icons": [
     {
-      "src": "/globe.svg",
+      "src": "/icon-192.png",
       "sizes": "192x192",
-      "type": "image/svg+xml"
+      "type": "image/png"
     },
     {
-      "src": "/globe.svg",
+      "src": "/icon-512.png",
       "sizes": "512x512",
-      "type": "image/svg+xml"
+      "type": "image/png"
     }
   ]
 }