feat(call): split resolution/fps in share picker + restore window state after fullscreen

ScreenSharePickerModal now exposes Auflösung (Auto · 720p · 1080p · 1440p
· 4K) and FPS (30 · 60) as separate pill rows instead of bundled quality
presets — users can pick "1440p · 30 fps" or "4K · 30 fps" which the old
preset list didn't surface. The underlying screenShareSettings framerateOverride
slot already existed; the modal just stopped resetting it to null on every
start and now plumbs the chosen FPS through to startScreenShare.

Cinema-mode fullscreen on Windows had two defects:

1. Maximized → fullscreen left the taskbar drawn on top of the window
   because DWM kept the maximized work-area constraints. We now unmaximize
   first so DWM recomposes cleanly and setFullScreen actually covers the
   whole monitor including the taskbar strip.

2. Esc out of cinema came back as a small floating window even when the
   user had been maximized before clicking the Vollbild button — the
   unmaximize from (1) was never undone. We now memo the pre-fullscreen
   maximized flag per window-id and call win.maximize() once the
   leave-full-screen event has fired.

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

apps/desktop/electron/modules/window-fullscreen.ts

@@ -9,6 +9,14 @@ import { BrowserWindow, ipcMain } from 'electron';
 import { CHANNELS } from '../ipc-types';
 
 export function register(mainWindow: BrowserWindow): void {
+  // Per-window maximize-before-fullscreen memo. We have to drop the
+  // maximized flag on Windows before setFullScreen so DWM recomposes
+  // cleanly (taskbar quirk), but Electron doesn't remember that the
+  // window WAS maximized — exiting fullscreen would leave it as a small
+  // floating window. Track it ourselves keyed by window-id so a future
+  // multi-window setup doesn't cross-pollute state.
+  const wasMaximized = new Map<number, boolean>();
+
   ipcMain.handle(CHANNELS.WINDOW_SET_FULLSCREEN, (evt, enabled: boolean) => {
     try {
       // Prefer the BrowserWindow that issued the IPC so multi-window setups
@@ -16,7 +24,38 @@ export function register(mainWindow: BrowserWindow): void {
       // registered against (matches autostart.ts's app-singleton shape).
       const win = BrowserWindow.fromWebContents(evt.sender) ?? mainWindow;
       if (!win || win.isDestroyed()) return;
-      win.setFullScreen(!!enabled);
+      const id = win.id;
+      if (enabled) {
+        // Windows DWM quirk: maximized → fullscreen sometimes leaves the
+        // taskbar drawn on top of the window because DWM keeps the
+        // maximized work-area constraints. Drop the maximize flag first
+        // so setFullScreen covers the whole monitor cleanly. Remember the
+        // pre-fullscreen state so the exit path can restore it.
+        if (process.platform === 'win32') {
+          const was = win.isMaximized();
+          wasMaximized.set(id, was);
+          if (was) win.unmaximize();
+        }
+        win.setFullScreen(true);
+      } else {
+        win.setFullScreen(false);
+        // Restore maximize if we dropped it on entry. setFullScreen(false)
+        // emits 'leave-full-screen' asynchronously; maximize() needs to
+        // wait until the window is back in normal mode or it silently
+        // no-ops. The event fires same-tick in Electron 33, but we listen
+        // for it once just to be safe across versions.
+        if (process.platform === 'win32' && wasMaximized.get(id)) {
+          wasMaximized.delete(id);
+          const restore = (): void => {
+            if (!win.isDestroyed()) win.maximize();
+          };
+          if (win.isFullScreen()) {
+            win.once('leave-full-screen', restore);
+          } else {
+            restore();
+          }
+        }
+      }
     } catch (err: unknown) {
       console.warn('window setFullscreen failed', err);
       throw err;