fix(panes): let toggleWindow be the authority, not a stale hasWindow() check

The tray menu asked "do we own a window for this pane?" and then acted on the
answer. Windows are destroyed asynchronously, so between the question and the
act the answer can go stale: hasWindow() says yes, the window is destroyed,
toggleWindow() returns false, the handler has already committed to the
main-process path and returns — and the click lands on nothing.

A tray item that silently does nothing is the worst possible failure here,
because the tray IS the recovery path when a pane is out of sight.

toggleWindow() already reports whether it did anything. Use that: if it toggled,
we're done; if it didn't, we never had that window (or just lost it), and only
the renderer can decide what opening the pane means — it might belong in the
dock, and its element lives there.

hasWindow()/hasPaneWindow() existed only to support the racy check, so they're
gone rather than left lying around for someone to reintroduce the race with.

Signed-off-by: topkoa <topkoa@gmail.com>

src/main/main.ts

@@ -128,7 +128,7 @@ import { installAppMenu } from './app-menu';
 import { sanitizeWindowBounds, MIN_WIDTH, MIN_HEIGHT } from './window-bounds';
 import {
     initPaneHosts, closeAllPanes, adoptPaneWindow, paneIdFromFrameName,
-    togglePaneWindow, showAllPaneWindows, hideAllPaneWindows, hasPaneWindow,
+    togglePaneWindow, showAllPaneWindows, hideAllPaneWindows,
 } from './pane-hosts';
 import { initTray, destroyTray } from './pane-tray';
 
@@ -1199,7 +1199,6 @@ async function startup(): Promise<void> {
         toggleWindow: togglePaneWindow,
         showAll: showAllPaneWindows,
         hideAll: hideAllPaneWindows,
-        hasWindow: hasPaneWindow,
     });
 
     // Install our application menu (replaces Electron's default so View →