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/electron/modules/shortcuts.ts

@@ -0,0 +1,86 @@
+// Global shortcuts — wraps Electron's globalShortcut, tracks registrations
+// by an opaque renderer-supplied id so the same accelerator can be
+// re-bound without the caller juggling state.
+//
+// PTT semantics are simulated: Electron's globalShortcut API only delivers
+// a "pressed" callback — it has no keyup / release event. We fire
+// SHORTCUT_EVT_FIRED on press, then after a 200ms timer fire
+// SHORTCUT_EVT_RELEASED. Known limitation; TODO: revisit with
+// `uiohook-napi` or `node-global-key-listener` if the press-and-release
+// UX is too loose.
+
+import { app, BrowserWindow, globalShortcut, ipcMain } from 'electron';
+
+import {
+  CHANNELS,
+  type ShortcutEvent,
+  type ShortcutKind,
+  type ShortcutRegisterArgs,
+} from '../ipc-types';
+
+interface Entry {
+  accelerator: string;
+  kind: ShortcutKind;
+}
+
+const registry = new Map<string, Entry>();
+
+export function register(mainWindow: BrowserWindow): void {
+  const send = (channel: string, payload: ShortcutEvent): void => {
+    if (mainWindow.isDestroyed()) return;
+    mainWindow.webContents.send(channel, payload);
+  };
+
+  ipcMain.handle(
+    CHANNELS.SHORTCUT_REGISTER,
+    async (_evt, args: ShortcutRegisterArgs): Promise<boolean> => {
+      const { id, accelerator, kind } = args;
+      const prev = registry.get(id);
+      if (prev) {
+        try {
+          globalShortcut.unregister(prev.accelerator);
+        } catch {
+          /* ignore */
+        }
+        registry.delete(id);
+      }
+      if (globalShortcut.isRegistered(accelerator)) {
+        return false;
+      }
+      const ok = globalShortcut.register(accelerator, () => {
+        const ts = Date.now();
+        send(CHANNELS.SHORTCUT_EVT_FIRED, { id, ts });
+        if (kind === 'ptt') {
+          setTimeout(() => {
+            send(CHANNELS.SHORTCUT_EVT_RELEASED, { id, ts: Date.now() });
+          }, 200);
+        }
+      });
+      if (!ok) return false;
+      registry.set(id, { accelerator, kind });
+      return true;
+    },
+  );
+
+  ipcMain.handle(CHANNELS.SHORTCUT_UNREGISTER, async (_evt, id: string): Promise<void> => {
+    const entry = registry.get(id);
+    if (!entry) return;
+    try {
+      globalShortcut.unregister(entry.accelerator);
+    } catch {
+      /* already gone */
+    }
+    registry.delete(id);
+  });
+
+  ipcMain.handle(CHANNELS.SHORTCUT_IS_REGISTERED, async (_evt, id: string): Promise<boolean> => {
+    const entry = registry.get(id);
+    if (!entry) return false;
+    return globalShortcut.isRegistered(entry.accelerator);
+  });
+
+  app.on('will-quit', () => {
+    globalShortcut.unregisterAll();
+    registry.clear();
+  });
+}