feat(calendar): add feed subscription, bulk export, share & Google Cal

- /api/kalender.ics SSR route: ICS feed of all calendar items (webcal-subscribable, Cache 1h)
- buildICSFeed() / downloadICSFeed() for multi-event ICS export
- googleCalUrl() deep-link pre-fills Google Calendar create form
- Web Share API per event (navigator.share on mobile, clipboard fallback on desktop)
  — "Kopiert\!" toast per event for 2s after clipboard write
- Actions bar (subscribe + bulk export) only rendered after onMount
  — Apple platforms: webcal:// link opens Calendar.app natively
  — All others: direct ICS download via <a download>

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/calendar-ics.ts

@@ -122,6 +122,72 @@ export function downloadICS(item: CalendarItemICS, filename: string): void {
   URL.revokeObjectURL(url);
 }
 
+/** Builds a VCALENDAR with multiple VEVENTs — for feed/bulk export. */
+export function buildICSFeed(items: CalendarItemICS[], calName = "Windwiderstand Termine"): string {
+  const now = new Date();
+  const lines: string[] = [
+    "BEGIN:VCALENDAR",
+    "VERSION:2.0",
+    "PRODID:-//windwiderstand.de//calendar//DE",
+    "CALSCALE:GREGORIAN",
+    "METHOD:PUBLISH",
+    foldLine(`X-WR-CALNAME:${escapeText(calName)}`),
+    "X-WR-TIMEZONE:Europe/Berlin",
+    "REFRESH-INTERVAL;VALUE=DURATION:PT1H",
+    "X-PUBLISHED-TTL:PT1H",
+  ];
+  for (const item of items) {
+    const start = item.start;
+    const end = item.end ?? new Date(start.getTime() + 60 * 60 * 1000);
+    const uid = item.uid ?? deterministicUid(item.title, start);
+    lines.push(
+      "BEGIN:VEVENT",
+      `UID:${uid}`,
+      `DTSTAMP:${fmtICSDate(now)}`,
+      `DTSTART:${fmtICSDate(start)}`,
+      `DTEND:${fmtICSDate(end)}`,
+      foldLine(`SUMMARY:${escapeText(item.title)}`),
+    );
+    if (item.description) lines.push(foldLine(`DESCRIPTION:${escapeText(item.description)}`));
+    if (item.location) lines.push(foldLine(`LOCATION:${escapeText(item.location)}`));
+    if (item.url) lines.push(foldLine(`URL:${item.url}`));
+    lines.push("END:VEVENT");
+  }
+  lines.push("END:VCALENDAR");
+  return lines.join("\r\n");
+}
+
+/** Triggers a browser download of a multi-event ICS file. */
+export function downloadICSFeed(items: CalendarItemICS[], filename: string): void {
+  if (typeof window === "undefined") return;
+  const safeName = filename.replace(/[/\\:*?"<>|]/g, "_") || "termine.ics";
+  const ics = buildICSFeed(items);
+  const blob = new Blob([ics], { type: "text/calendar;charset=utf-8" });
+  const url = URL.createObjectURL(blob);
+  const a = document.createElement("a");
+  a.href = url;
+  a.download = safeName.endsWith(".ics") ? safeName : `${safeName}.ics`;
+  document.body.appendChild(a);
+  a.click();
+  document.body.removeChild(a);
+  URL.revokeObjectURL(url);
+}
+
+/** Deep-link to Google Calendar's pre-filled create form. */
+export function googleCalUrl(item: CalendarItemICS): string {
+  const fmt = (d: Date) =>
+    d.toISOString().replace(/[-:]/g, "").replace(/\.\d+Z$/, "Z");
+  const end = item.end ?? new Date(item.start.getTime() + 60 * 60 * 1000);
+  const params = new URLSearchParams({
+    action: "TEMPLATE",
+    text: item.title,
+    dates: `${fmt(item.start)}/${fmt(end)}`,
+  });
+  if (item.description) params.set("details", item.description);
+  if (item.location) params.set("location", item.location);
+  return `https://calendar.google.com/calendar/render?${params}`;
+}
+
 /** OpenStreetMap search URL for an address or place name. */
 export function mapsUrl(location: string): string {
   return `https://www.openstreetmap.org/search?query=${encodeURIComponent(location)}`;

src/lib/iconify-mdi-subset.generated.json

@@ -72,9 +72,15 @@
     "download": {
       "body": "<path fill=\"currentColor\" d=\"M5 20h14v-2H5m14-9h-4V3H9v6H5l7 7z\"/>"
     },
+    "google": {
+      "body": "<path fill=\"currentColor\" d=\"M21.35 11.1h-9.17v2.73h6.51c-.33 3.81-3.5 5.44-6.5 5.44C8.36 19.27 5 16.25 5 12c0-4.1 3.2-7.27 7.2-7.27c3.09 0 4.9 1.97 4.9 1.97L19 4.72S16.56 2 12.1 2C6.42 2 2.03 6.8 2.03 12c0 5.05 4.13 10 10.22 10c5.35 0 9.25-3.67 9.25-9.09c0-1.15-.15-1.81-.15-1.81\"/>"
+    },
     "calendar-search": {
       "body": "<path fill=\"currentColor\" d=\"M15.5 12c2.5 0 4.5 2 4.5 4.5c0 .88-.25 1.71-.69 2.4l3.08 3.1L21 23.39l-3.12-3.07c-.69.43-1.51.68-2.38.68c-2.5 0-4.5-2-4.5-4.5s2-4.5 4.5-4.5m0 2a2.5 2.5 0 0 0-2.5 2.5a2.5 2.5 0 0 0 2.5 2.5a2.5 2.5 0 0 0 2.5-2.5a2.5 2.5 0 0 0-2.5-2.5M19 8H5v11h4.5c.31.75.76 1.42 1.31 2H5a2 2 0 0 1-2-2V5c0-1.11.89-2 2-2h1V1h2v2h8V1h2v2h1a2 2 0 0 1 2 2v8.03c-.5-.81-1.2-1.49-2-2.03z\"/>"
     },
+    "calendar-plus": {
+      "body": "<path fill=\"currentColor\" d=\"M19 19V8H5v11zM16 1h2v2h1a2 2 0 0 1 2 2v14c0 1.11-.89 2-2 2H5a2 2 0 0 1-2-2V5c0-1.11.89-2 2-2h1V1h2v2h8zm-5 8.5h2v3h3v2h-3v3h-2v-3H8v-2h3z\"/>"
+    },
     "arrow-right": {
       "body": "<path fill=\"currentColor\" d=\"M4 11v2h12l-5.5 5.5l1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5L16 11z\"/>"
     },

src/lib/translations.ts

@@ -137,6 +137,13 @@ const TRANSLATION_KEYS = [
   "calendar_untitled",
   "calendar_show_more",
   "calendar_show_less",
+  "calendar_subscribe",
+  "calendar_subscribe_aria",
+  "calendar_export_all",
+  "calendar_add_to_google",
+  "calendar_share",
+  "calendar_share_copied",
+  "calendar_share_aria",
   "post_overview_all",
   "blog_search_label",
   "blog_search_placeholder",

src/routes/api/kalender.ics/+server.ts

@@ -0,0 +1,57 @@
+import type { RequestHandler } from '@sveltejs/kit';
+import { env } from '$env/dynamic/public';
+import { getCalendarItems } from '$lib/cms';
+import { buildICSFeed, type CalendarItemICS } from '$lib/calendar-ics';
+import type { CalendarItemData } from '$lib/block-types';
+
+function parseDate(iso: string | undefined | null): Date | null {
+  if (!iso) return null;
+  const d = new Date(iso);
+  return isNaN(d.getTime()) ? null : d;
+}
+
+function locationText(loc: unknown): string {
+  if (typeof loc === 'string') return loc;
+  if (loc && typeof loc === 'object') {
+    const t = (loc as { text?: unknown }).text;
+    if (typeof t === 'string') return t;
+  }
+  return '';
+}
+
+export const GET: RequestHandler = async () => {
+  const siteName = env.PUBLIC_SITE_NAME || 'Windwiderstand';
+
+  let rawItems: Awaited<ReturnType<typeof getCalendarItems>> = [];
+  try {
+    rawItems = await getCalendarItems();
+  } catch {
+    rawItems = [];
+  }
+
+  const icsItems: CalendarItemICS[] = rawItems
+    .flatMap((raw) => {
+      const item = raw as unknown as CalendarItemData;
+      const start = parseDate(item.terminZeit);
+      if (!start) return [];
+      const end = parseDate(item.terminEnde ?? null) ?? undefined;
+      const entry: CalendarItemICS = {
+        title: item.title || 'Termin',
+        start,
+        end,
+        description: (item as { description?: string }).description ?? undefined,
+        location: locationText((item as { location?: unknown }).location) || undefined,
+      };
+      return [entry];
+    });
+
+  const body = buildICSFeed(icsItems, `${siteName} – Termine`);
+
+  return new Response(body, {
+    headers: {
+      'Content-Type': 'text/calendar; charset=utf-8',
+      'Content-Disposition': 'inline; filename="windwiderstand-termine.ics"',
+      'Cache-Control': 'public, max-age=3600',
+    },
+  });
+};