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/pages/ChangelogPage.tsx

@@ -0,0 +1,120 @@
+import { useEffect, useState } from 'react';
+
+import { fetchChangelog, type ChangelogEntry } from '../lib/changelog';
+import { SparklesIcon, SpinnerIcon } from '../components/icons';
+
+const PAGE_SIZE = 10;
+
+export function ChangelogPage() {
+  const [entries, setEntries] = useState<ChangelogEntry[] | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [visible, setVisible] = useState(PAGE_SIZE);
+
+  useEffect(() => {
+    let cancelled = false;
+    void (async () => {
+      try {
+        const list = await fetchChangelog();
+        if (!cancelled) setEntries(list);
+      } catch (err: unknown) {
+        if (!cancelled) {
+          setError(err instanceof Error ? err.message : 'Konnte Changelog nicht laden.');
+        }
+      }
+    })();
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
+  return (
+    <div className="min-h-full bg-surface-3 text-fg">
+      <div className="mx-auto flex max-w-3xl flex-col gap-6 px-6 py-8">
+        <header className="mb-2 flex items-start gap-3">
+          <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-xl bg-accent/15 text-accent">
+            <SparklesIcon className="h-5 w-5" />
+          </div>
+          <div>
+            <h1 className="font-display text-2xl font-semibold tracking-tight text-fg">
+              Was ist neu
+            </h1>
+            <p className="mt-0.5 text-sm text-fg-muted">
+              Alle Änderungen in dieser App, neueste zuerst.
+            </p>
+          </div>
+        </header>
+
+        {entries === null && !error && (
+          <div className="flex items-center gap-2 rounded-xl border border-line bg-surface-2 p-6 text-sm text-fg-muted">
+            <SpinnerIcon className="h-4 w-4 text-accent" />
+            <span>Lade Changelog…</span>
+          </div>
+        )}
+
+        {error && (
+          <div className="rounded-xl border border-rose-500/30 bg-rose-500/10 p-4 text-sm text-rose-600 dark:text-rose-200">
+            <p className="font-semibold">Fehler beim Laden</p>
+            <p className="mt-1 text-xs opacity-90">{error}</p>
+          </div>
+        )}
+
+        {entries !== null && entries.length === 0 && !error && (
+          <div className="rounded-xl border border-line bg-surface-2 p-8 text-center text-sm text-fg-muted">
+            Noch keine Einträge vorhanden.
+          </div>
+        )}
+
+        {entries && entries.length > 0 && (
+          <ol className="flex flex-col gap-4">
+            {entries.slice(0, visible).map((entry) => (
+              <li
+                key={entry.version}
+                className="rounded-2xl border border-line bg-surface-2 p-5 shadow-sm"
+              >
+                <div className="flex flex-wrap items-baseline justify-between gap-3">
+                  <h2 className="font-display text-lg font-semibold tracking-tight text-fg">
+                    v{entry.version}
+                  </h2>
+                  <time
+                    dateTime={entry.pub_date}
+                    className="text-xs tabular-nums text-fg-muted"
+                  >
+                    {formatDate(entry.pub_date)}
+                  </time>
+                </div>
+                <p className="mt-3 whitespace-pre-line break-words text-sm leading-relaxed text-fg">
+                  {entry.notes}
+                </p>
+              </li>
+            ))}
+            {visible < entries.length && (
+              <li>
+                <button
+                  type="button"
+                  onClick={() => setVisible((n) => n + PAGE_SIZE)}
+                  className="inline-flex w-full cursor-pointer items-center justify-center rounded-lg border border-line bg-surface-2 px-3 py-2.5 text-sm font-semibold text-fg transition hover:bg-surface-3 focus:outline-none focus-visible:ring-2 focus-visible:ring-accent/40"
+                >
+                  Mehr laden ({entries.length - visible} verbleibend)
+                </button>
+              </li>
+            )}
+          </ol>
+        )}
+      </div>
+    </div>
+  );
+}
+
+function formatDate(iso: string): string {
+  try {
+    const d = new Date(iso);
+    if (Number.isNaN(d.getTime())) return iso;
+    return d.toLocaleDateString('de-DE', {
+      year: 'numeric',
+      month: 'short',
+      day: 'numeric',
+    });
+  } catch {
+    return iso;
+  }
+}