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/native/audio-loopback/package.json

@@ -0,0 +1,32 @@
+{
+  "name": "@chatapp/audio-loopback-native",
+  "version": "0.1.0",
+  "private": true,
+  "description": "Native Windows process-loopback audio capture addon (excludes our own PID tree)",
+  "main": "index.js",
+  "types": "index.d.ts",
+  "files": [
+    "index.js",
+    "index.d.ts",
+    "*.node"
+  ],
+  "napi": {
+    "name": "audio-loopback",
+    "triples": {
+      "defaults": false,
+      "additional": [
+        "x86_64-pc-windows-msvc"
+      ]
+    }
+  },
+  "scripts": {
+    "build": "napi build --platform --release",
+    "build:debug": "napi build --platform"
+  },
+  "devDependencies": {
+    "@napi-rs/cli": "^2.18.0"
+  },
+  "engines": {
+    "node": ">= 18"
+  }
+}