fix: replace ASCII closing quotes with German U+201C in „..." pairs

25 occurrences in DOSSIER.md and 1 in templates/cover.html.
HTML attribute quotes left untouched.

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

templates/cover.html

@@ -491,7 +491,7 @@
         <p class="back-ornament-bottom">· · ·</p>
         <div class="back-bottom">
           <p class="back-tagline">
-            „Die schönsten Welten sind nur<br>mit geschlossenen Augen zu erreichen."
+            „Die schönsten Welten sind nur<br>mit geschlossenen Augen zu erreichen.“
           </p>
           {# Empty white box — KDP places the ISBN barcode here automatically #}
           <div class="barcode-placeholder"></div>