fix(theme): give the menu acrylic the card blur radius

Every panel class samples one shared blur texture, so a menu asking for
a different blur radius than cards could not actually get it. All it did
was force a second full-screen blur pass each frame as the radius
flipped between the card and menu values, and let whichever class drew
last decide the radius for everything.

- Setting the acrylic theme now copies the card blur radius onto the
  menu class, so menus and cards share one radius and the blur runs
  once per frame. The first-use default path goes through the same
  setter so it is covered too.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui/theme.cpp

@@ -181,8 +181,7 @@ AcrylicTheme GetLightAcrylicTheme()
 const AcrylicTheme& GetCurrentAcrylicTheme()
 {
     if (!s_acrylicThemeInitialized) {
-        s_currentAcrylicTheme = GetDragonXAcrylicTheme();
-        s_acrylicThemeInitialized = true;
+        SetCurrentAcrylicTheme(GetDragonXAcrylicTheme());
     }
     return s_currentAcrylicTheme;
 }
@@ -190,6 +189,10 @@ const AcrylicTheme& GetCurrentAcrylicTheme()
 void SetCurrentAcrylicTheme(const AcrylicTheme& theme)
 {
     s_currentAcrylicTheme = theme;
+    // Every panel class samples ONE shared blur texture, so a per-class radius cannot be honoured
+    // anyway: it only makes applyBlur() re-blur twice per frame (card <-> menu) and lets the last
+    // radius drawn win for all cards. Menus use the card radius.
+    s_currentAcrylicTheme.menu.blurRadius = s_currentAcrylicTheme.card.blurRadius;
     s_acrylicThemeInitialized = true;
 }