feat(desktop): port v0.11.4-v0.15.2 from Tauri to Electron + Discord-parity audio (v0.16.0)

Chronological port of every Tauri release commit (v0.11.4 -> v0.15.2)
into the Electron rebuild, plus Discord-style audio handling that goes
beyond the Tauri original.

Highlights:
  - All 17 Tauri release commits ported (audio fixes, custom notification
    sound, Discord-style chat UX, profile banner, changelog page,
    Discord-parity call UX, screen-share echo + re-watch UX, audio-loop
    fix).
  - Native napi-rs audio-loopback addon with WASAPI process-loopback:
      * EXCLUDE_TARGET_PROCESS_TREE for full-screen shares -> peers
        never hear themselves echoed back through the capture.
      * INCLUDE_TARGET_PROCESS_TREE for window shares -> only the
        picked window's audio is captured, not the whole OS mixer
        (Discord parity).
      * HWND -> PID resolution via Win32 GetWindowThreadProcessId.
  - Discord-style screen-source picker (thumbnail grid, screens vs
    apps tabs, live-refreshing thumbnails).
  - Hash routing fix for packaged builds (file:// can't resolve
    BrowserRouter paths).
  - Tauri sources removed (apps/desktop/src-tauri).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/desktop/src/components/UserBar.tsx

@@ -83,13 +83,13 @@ export function UserBar() {
         onClick={() => setOpen((v) => !v)}
         aria-haspopup="menu"
         aria-expanded={open}
-        className="flex w-full cursor-pointer items-center gap-3 rounded-lg px-2 py-2 text-left transition hover:bg-surface-3 focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40"
+        className="flex w-full cursor-pointer items-center gap-3 rounded-lg px-2 py-2 text-left transition hover:bg-surface-3 focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40 dark:hover:bg-[#383a40]"
       >
         <div className="relative">
           <Avatar
             url={profile?.avatarUrl ?? null}
             displayName={profile?.displayName ?? profile?.username}
-            className="h-9 w-9 text-sm"
+            className="h-10 w-10 text-sm"
           />
           <span
             className={
@@ -99,9 +99,7 @@ export function UserBar() {
           />
         </div>
         <div className="min-w-0 flex-1">
-          <p className="truncate text-sm font-medium text-fg">
-            {profile?.displayName ?? '—'}
-          </p>
+          <p className="truncate text-sm font-medium text-fg">{profile?.displayName ?? '—'}</p>
           <p className="truncate text-xs text-fg-muted">{subtitle}</p>
         </div>
         <ChevronDownIcon
@@ -112,7 +110,7 @@ export function UserBar() {
       {open && (
         <div
           role="menu"
-          className="absolute bottom-full left-0 right-0 mb-2 overflow-hidden rounded-lg border border-line bg-surface-3 shadow-xl"
+          className="absolute bottom-full left-0 right-0 mb-2 overflow-hidden rounded-lg border border-line bg-surface-3 shadow-xl dark:bg-[#313338]"
         >
           <div className="border-b border-line p-2">
             <input
@@ -135,7 +133,7 @@ export function UserBar() {
                 defaultValue: 'Status setzen…',
               })}
               maxLength={STATUS_MAX}
-              className="w-full rounded-md border border-line bg-surface-2 px-2 py-1.5 text-sm text-fg placeholder-fg-muted outline-none focus:border-accent"
+              className="w-full rounded-md border border-line bg-surface-2 px-2 py-1.5 text-sm text-fg placeholder-fg-muted outline-none focus:border-accent dark:bg-[#383a40]"
             />
           </div>
           {PRESENCE_OPTIONS.map((opt) => (
@@ -146,13 +144,11 @@ export function UserBar() {
               aria-checked={opt === presence}
               onClick={() => void changePresence(opt)}
               disabled={busy}
-              className="flex w-full cursor-pointer items-center gap-3 px-3 py-2 text-left text-sm text-fg transition hover:bg-surface-2 disabled:opacity-50"
+              className="flex w-full cursor-pointer items-center gap-3 px-3 py-2 text-left text-sm text-fg transition hover:bg-surface-2 disabled:opacity-50 dark:hover:bg-[#383a40]"
             >
               <span className={'h-2.5 w-2.5 rounded-full ' + PRESENCE_DOT[opt]} />
               <span className="flex-1">{t('app:presence.' + opt)}</span>
-              {opt === presence && (
-                <span className="text-xs text-accent">●</span>
-              )}
+              {opt === presence && <span className="text-xs text-accent">●</span>}
             </button>
           ))}
         </div>