fix(glass): solidify the translucent (backdrop-on) glass tier

With a background image on, glass surfaces used surface-alpha 50% + 10px blur, so the feed read
straight THROUGH the nav/menus/popovers (user-reported: distractingly transparent). Raised to
72%/80%/85% + 14px blur — the backdrop image still shows as soft colour, but content behind no longer
punches through. Verified in-browser: nav bg alpha 0.5 -> 0.72, no inline override on a clean pref.

frontend/src/lib/releaseNotes.ts

@@ -14,6 +14,13 @@ export interface ReleaseEntry {
 }
 
 export const RELEASE_NOTES: ReleaseEntry[] = [
+  {
+    version: "0.60.1",
+    date: "2026-08-08",
+    fixes: [
+      "With a background image on, the frosted panels (nav, menus, dialogs) are less see-through — the content behind them no longer reads through and distracts.",
+    ],
+  },
   {
     version: "0.60.0",
     date: "2026-08-08",