feat(calendar-compact): polish + global not-prose opt-out support

CalendarCompact:
- denser layout (smaller padding/font/badge), header icon size-8
- icon stein-900 (black), subtle wald gradient background
- rounded-sm to match design tokens (was rounded-lg)
- list items link to linkTo + "#event-<slug>" anchor; <svelte:element>
  falls back to div when no linkTo is set
- not-prose on root so global content margins/list/link rules don't
  apply to the card subtree

blog-utils.resolveCalendarBlocks:
- when items array is empty, fall back to the full calendar_item pool
  (both default and compact variant get this) — saves editors from
  re-listing items on every page.

app.css: add `:where(:not(.not-prose *))` to .content p/h1-h4,
main a (link colour + underline), main ul/ol so subtrees marked
not-prose stop inheriting the global prose-like defaults.

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

src/lib/blog-utils.ts

@@ -593,6 +593,13 @@ export async function resolveCalendarBlocks(
         resolve: "items",
       });
       const raw = calendar?.items ?? rawItems;
+      // Leere items-Liste → alle calendar_items aus der Collection (Pool).
+      // Greift sowohl für default-Variante als auch compact-Anteaser.
+      if (raw.length === 0) {
+        const pool = (await getCalendarItems({ locale: "de" })) as unknown as CalendarItemData[];
+        (item as { items?: CalendarItemData[] }).items = pool;
+        continue;
+      }
       const settled = await Promise.all(
         raw.map(async (x): Promise<CalendarItemData | null> => {
           if (