chore(desktop): release v0.18.8

The inner cards (Nachrichten-Ton / Klingelton / Audio-Gerät / Hotkeys /
…) looked like they had a stark white outline. The cause: --color-line
is a semi-transparent white token, and applying the `/60` alpha modifier
in `border-line/60` overrides the original alpha — so the inner border
ended up brighter than the outer Section's normal `border-line`.

Drop the border entirely. Background tint + caps heading is enough
grouping signal in a tab-pattern panel.

apps/desktop/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@chat-app/desktop",
-  "version": "0.18.7",
+  "version": "0.18.8",
   "private": true,
   "description": "Electron desktop client (Windows / macOS / Linux)",
   "type": "module",

apps/desktop/src/pages/SettingsPage.tsx

@@ -1310,9 +1310,13 @@ function Section({
 
 // Sub-heading inside a Section — used to chunk dense sections like Voice into
 // smaller named groups (Audio-Gerät / Qualität / PTT / Hotkeys / E2EE).
+// No border: `--color-line` is already a semi-transparent token, and applying
+// the `/60` opacity modifier brightens it (Tailwind overrides the original
+// alpha) which made the sub-cards look harsher than the outer Section. Plain
+// background tint + caps heading carry the grouping signal on their own.
 function SubSection({ title, children }: { title: string; children: React.ReactNode }) {
   return (
-    <div className="space-y-2 rounded-xl border border-line/60 bg-surface-3/40 p-4">
+    <div className="space-y-2 rounded-xl bg-surface-3/50 p-4">
       <h3 className="text-[11px] font-semibold uppercase tracking-[0.1em] text-fg-muted">
         {title}
       </h3>