fix: bundle f12-rocks onepager photos locally

Hotlinked images from f12.rocks were blocked cross-origin; download
640px WebPs into the repo and reference them with relative paths.

Co-authored-by: Cursor <cursoragent@cursor.com>

public/f12-rocks/index.html

@@ -259,35 +259,35 @@
 
     <div class="photo-grid" aria-label="Auswahl aus dem @f12.rocks Feed">
       <img
-        src="https://f12.rocks/images/20260703_Hellraisers_TheShape_Schlossplatz/640/20260704_0001.webp"
+        src="images/hellraisers-schlossplatz.webp"
         alt="Konzertfoto: Hellraisers & The Shape am Schlossplatz"
         width="640"
         height="958"
         loading="eager"
       >
       <img
-        src="https://f12.rocks/images/20260620_ALB_MFF/640/20260620_5045.webp"
+        src="images/crusaders-sideline.webp"
         alt="Football: Crusaders an der Sideline"
         width="640"
         height="427"
         loading="lazy"
       >
       <img
-        src="https://f12.rocks/images/20260526_Baxxter_Shooting/640/20260525_0343.webp"
+        src="images/baxxter-shooting.webp"
         alt="Band-Shooting: Baxxter Boys"
         width="640"
         height="428"
         loading="lazy"
       >
       <img
-        src="https://f12.rocks/images/20260516_Hischaboggl_MieV/640/20260517_1611.webp"
+        src="images/miev-konzert.webp"
         alt="Live-Konzert im MieV"
         width="640"
         height="427"
         loading="lazy"
       >
       <img
-        src="https://f12.rocks/images/20260517_ALB_BIB/640/20260517_AHC-BIB_07_Schwenk.webp"
+        src="images/crusaders-gameday.webp"
         alt="American Football: Crusaders Game Day"
         width="640"
         height="427"