fix(v1.7.3): clean wordmark PNG + descender headroom

Regenerate assets/beep-wordmark.png (and -blue) as a clean transparent
render of the 3D logo, replacing the corrupted files — fixes the feed
header image. Bump the inline-SVG viewBox so the "p" descender never clips.

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

includes/helpers.php

@@ -59,9 +59,9 @@ function beep_logo_svg() {
  *
  * Rendered as a crisp inline SVG recreation of the 3D extruded brand logo —
  * a blue-violet face with a darker-blue depth and navy outline. Stays sharp at
- * any size and ships as ~1KB of markup (no image request). The bundled
- * beep-wordmark.png assets are corrupted, which is why we draw it as vector.
- * To swap in a real image once you have a clean asset, hook the filter:
+ * any size and ships as ~1KB of markup (no image request). The matching raster
+ * version lives at assets/beep-wordmark.png (used in the feed header).
+ * To swap in the PNG here instead, hook the filter:
  *   add_filter('beep_post_wordmark', fn() => '<img class="beep-post-wordmark" src="...">');
  */
 function beep_post_wordmark() {
@@ -74,7 +74,7 @@ function beep_post_wordmark() {
         $extrude .= '<text x="' . $x . '" y="' . $y . '" fill="#2A2AAE">Beep!</text>';
     }
 
-    $svg = '<svg class="beep-post-wordmark" viewBox="0 0 168 68"'
+    $svg = '<svg class="beep-post-wordmark" viewBox="0 0 168 72"'
         . ' role="img" aria-label="Beep!" xmlns="http://www.w3.org/2000/svg">'
         . '<g font-family="&quot;Arial Black&quot;,&quot;Arial Bold&quot;,Arial,Helvetica,sans-serif"'
         . ' font-weight="900" font-size="52" letter-spacing="-1">'