feat(termin): Termin-Detail unter /kalender/termin/<slug>, 302 von alt

Route /termin/[slug] -> /kalender/termin/[slug] verschoben, alte URL
302-redirect (QR-Codes/geteilte Links bleiben gueltig). Breadcrumb 3-stufig
(Start > Kalender > Titel). QR-/Detail-/OG-Links auf neuen Pfad.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/routes/kalender/termin/[slug]/+page.server.ts

@@ -0,0 +1,189 @@
+import type { PageServerLoad } from "./$types";
+import { error } from "@sveltejs/kit";
+import { getCalendarItemBySlug } from "$lib/cms";
+import { marked } from "$lib/markdown-safe";
+import { env } from "$env/dynamic/public";
+
+/**
+ * Eigenständige Detail-Seite pro Termin: alle Infos + Aktionen ungekürzt,
+ * eigene OG-Tags (Link-Previews FB/WhatsApp/Twitter) und ein Link zum
+ * Kalender (KEIN Redirect mehr — die Seite ist das Ziel des QR-/Direktlinks).
+ *
+ * terminZeit ist mit Offset gespeichert (z. B. 10:00+02:00). Labels müssen in
+ * Europe/Berlin gerendert werden, sonst zeigt der SSR-Prozess (Server-TZ=UTC)
+ * 2h zu früh.
+ */
+const TZ = "Europe/Berlin";
+
+export const load: PageServerLoad = async ({ params, setHeaders }) => {
+  const slug = params.slug;
+  const rawItem = await getCalendarItemBySlug(slug, { locale: "de" });
+  if (!rawItem) throw error(404, "Termin nicht gefunden");
+  const item = rawItem as typeof rawItem & {
+    location?: unknown;
+    description?: string;
+    terminEnde?: string;
+    tags?: string[];
+    image?: unknown;
+    attachment?: { src?: string; label?: string };
+    link?: unknown;
+  };
+
+  const siteBaseUrl = (env.PUBLIC_SITE_URL || "").replace(/\/$/, "");
+  const title = (item.title ?? "Termin").trim();
+  const terminZeit = item.terminZeit;
+  const terminEnde = item.terminEnde ?? null;
+  const hasTime = !!terminZeit && !/T00:00:00/.test(terminZeit);
+
+  const weekdayLabel = terminZeit
+    ? new Date(terminZeit).toLocaleDateString("de-DE", { weekday: "long", timeZone: TZ })
+    : "";
+  const dateLabel = terminZeit
+    ? new Date(terminZeit).toLocaleDateString("de-DE", {
+        day: "2-digit",
+        month: "long",
+        year: "numeric",
+        timeZone: TZ,
+      })
+    : "";
+  const timeLabel = hasTime
+    ? new Date(terminZeit).toLocaleTimeString("de-DE", {
+        hour: "2-digit",
+        minute: "2-digit",
+        timeZone: TZ,
+      }) + " Uhr"
+    : "";
+  const endDateLabel =
+    terminEnde && !/T00:00:00/.test(terminEnde)
+      ? new Date(terminEnde).toLocaleDateString("de-DE", {
+          day: "2-digit",
+          month: "long",
+          year: "numeric",
+          timeZone: TZ,
+        })
+      : "";
+
+  const locObj =
+    typeof item.location === "object" && item.location !== null
+      ? (item.location as { text?: string; lat?: number; lng?: number })
+      : null;
+  const locationText = locObj
+    ? (locObj.text ?? "").trim() || null
+    : typeof item.location === "string"
+      ? item.location.trim() || null
+      : null;
+  const hasCoords =
+    !!locObj && typeof locObj.lat === "number" && typeof locObj.lng === "number";
+
+  // Externer Link / Post-Link
+  let externalLink: string | null = null;
+  const link = item.link as { url?: string; _slug?: string } | string | undefined;
+  if (typeof link === "string" && link) externalLink = link;
+  else if (link && typeof link === "object") {
+    if (link.url) externalLink = link.url;
+    else if (link._slug) externalLink = `/post/${encodeURIComponent(link._slug)}`;
+  }
+
+  const descriptionHtml = item.description
+    ? (marked.parse(item.description) as string)
+    : "";
+  const descriptionPlain = descriptionHtml
+    .replace(/<[^>]+>/g, " ")
+    .replace(/\s+/g, " ")
+    .trim();
+
+  const tags = Array.isArray(item.tags) ? item.tags.filter((t) => typeof t === "string") : [];
+
+  const seoDescription = [
+    dateLabel + (timeLabel ? `, ${timeLabel}` : ""),
+    locationText,
+    descriptionPlain ? descriptionPlain.slice(0, 200) : null,
+  ]
+    .filter(Boolean)
+    .join(" · ");
+
+  const socialImage = `${siteBaseUrl}/api/social/calendar/${encodeURIComponent(slug)}?format=og`;
+  const calendarUrl = `/kalender/#event-${slug}`;
+  const canonical = `${siteBaseUrl}/kalender/termin/${encodeURIComponent(slug)}/`;
+
+  // schema.org Event — Rich-Result/SEO für Termine (Datum, Ort, Veranstalter).
+  const jsonLd = terminZeit
+    ? [
+        {
+          "@context": "https://schema.org",
+          "@type": "Event",
+          name: title,
+          startDate: terminZeit,
+          ...(terminEnde ? { endDate: terminEnde } : {}),
+          eventAttendanceMode: "https://schema.org/OfflineEventAttendanceMode",
+          eventStatus: "https://schema.org/EventScheduled",
+          ...(siteBaseUrl ? { url: canonical } : {}),
+          inLanguage: "de-DE",
+          ...(descriptionPlain ? { description: descriptionPlain.slice(0, 500) } : {}),
+          image: socialImage,
+          organizer: {
+            "@type": "Organization",
+            name: "Windwiderstand Thüringen",
+            ...(siteBaseUrl ? { url: siteBaseUrl } : {}),
+          },
+          ...(locationText
+            ? {
+                location: {
+                  "@type": "Place",
+                  name: locationText,
+                  ...(hasCoords
+                    ? {
+                        geo: {
+                          "@type": "GeoCoordinates",
+                          latitude: locObj!.lat,
+                          longitude: locObj!.lng,
+                        },
+                      }
+                    : {}),
+                },
+              }
+            : {}),
+        },
+      ]
+    : [];
+
+  const breadcrumbItems = [
+    { label: "Start", href: "/" },
+    { label: "Kalender", href: "/kalender/" },
+    { label: title },
+  ];
+
+  setHeaders({
+    "cache-control": "public, s-maxage=300, stale-while-revalidate=3600",
+  });
+
+  return {
+    seoTitle: `${title} – Windwiderstand Thüringen`,
+    seoDescription,
+    socialImage,
+    ogType: "article" as const,
+    jsonLd,
+    breadcrumbItems,
+    calendarUrl,
+    item: {
+      slug,
+      title,
+      terminZeit: terminZeit ?? null,
+      terminEnde,
+      hasTime,
+      weekdayLabel,
+      dateLabel,
+      timeLabel,
+      endDateLabel,
+      locationText,
+      descriptionHtml,
+      tags,
+      image: item.image ?? null,
+      attachment:
+        item.attachment && item.attachment.src
+          ? { src: item.attachment.src, label: item.attachment.label ?? "Anhang" }
+          : null,
+      externalLink,
+    },
+  };
+};