refactor(post-events): read event data from resolved calendarItem

Replace direct post.isEvent/eventDate/eventLocation reads with
getPostEventInfo() helper that derives info from the resolved
calendarItem reference. Loaders now resolve "calendarItem" and request
that field instead of legacy flat properties.

Also regenerate iconify mdi subset (map-marker-outline, download,
google, calendar-search, refresh).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/routes/post/[slug]/+page.server.ts

@@ -12,6 +12,7 @@ import {
   resolveDeadlineBannerBlocks,
   getPostImageField,
   formatPostDate,
+  getPostEventInfo,
 } from '$lib/blog-utils';
 import { POST_RESOLVE, POST_SOCIAL_IMAGE_TRANSFORM, SITE_NAME } from '$lib/constants';
 import { env } from '$env/dynamic/public';
@@ -110,8 +111,9 @@ export const load: PageServerLoad = async ({ params, locals, url, setHeaders })
   const postHeadline = post.headline ?? post.linkName ?? slug;
   const postDescription = post.seoDescription ?? post.subheadline ?? post.excerpt ?? '';
 
-  const isEvent = !!(post as { isEvent?: boolean }).isEvent;
-  const eventDateRaw = (post as { eventDate?: string }).eventDate ?? null;
+  const eventInfo = getPostEventInfo(post);
+  const isEvent = eventInfo.isEvent;
+  const eventDateRaw = eventInfo.eventDate;
   const eventDateLabel =
     isEvent && eventDateRaw
       ? new Date(eventDateRaw).toLocaleDateString('de-DE', {
@@ -123,9 +125,7 @@ export const load: PageServerLoad = async ({ params, locals, url, setHeaders })
           minute: '2-digit',
         })
       : null;
-  const eventLocation = isEvent
-    ? ((post as { eventLocation?: { text?: string; lat?: number; lng?: number } }).eventLocation ?? null)
-    : null;
+  const eventLocation = eventInfo.eventLocation;
 
   const hasCoords = !!(eventLocation?.lat && eventLocation?.lng);
   const _lat = eventLocation?.lat ?? 0;