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/App.tsx

@@ -1,5 +1,5 @@
 import { lazy, Suspense } from 'react';
-import { BrowserRouter, Navigate, Outlet, Route, Routes } from 'react-router-dom';
+import { HashRouter, Navigate, Outlet, Route, Routes } from 'react-router-dom';
 
 import { AppShell } from './components/AppShell';
 import { CrashToast } from './components/CrashToast';
@@ -31,6 +31,9 @@ const FriendsPage = lazy(() =>
 const SettingsPage = lazy(() =>
   import('./pages/SettingsPage').then((m) => ({ default: m.SettingsPage })),
 );
+const ChangelogPage = lazy(() =>
+  import('./pages/ChangelogPage').then((m) => ({ default: m.ChangelogPage })),
+);
 
 function RouteSuspense({ children }: { children: React.ReactNode }) {
   return (
@@ -64,7 +67,7 @@ export function App() {
           <FriendshipsProvider>
             <ConversationsProvider>
               <CallProvider>
-                <BrowserRouter
+                <HashRouter
                   future={{
                     // Opt into v7 behaviour early so the upgrade is a no-op:
                     // - `v7_startTransition` wraps navigations in startTransition
@@ -136,6 +139,16 @@ export function App() {
                               }
                             />
                           </Route>
+                          <Route element={<RouteBoundary scope="changelog" />}>
+                            <Route
+                              path="/changelog"
+                              element={
+                                <RouteSuspense>
+                                  <ChangelogPage />
+                                </RouteSuspense>
+                              }
+                            />
+                          </Route>
                           <Route element={<RequireAdmin />}>
                             <Route element={<RouteBoundary scope="admin" />}>
                               <Route
@@ -155,7 +168,7 @@ export function App() {
                   </Routes>
                   <UpdateToast />
                   <CrashToast />
-                </BrowserRouter>
+                </HashRouter>
               </CallProvider>
             </ConversationsProvider>
           </FriendshipsProvider>