ui: 720p-safe default window size + tighter layout minimums (T5.1)

Lower default from 1120×720 to 1024×660 so the window opens fully
visible on 1366×768 / 720p screens. Reduce minJobsSidebarWidth (480→400)
and commandOutputScroll min size (520×160→460×120) to match; the layout
engine enforces these as the natural minimum, keeping the UI usable at
the smaller default.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ui/run.go

@@ -48,7 +48,7 @@ func Run(startInTray bool) {
 
 	w := a.NewWindow("GoSentry " + app.Version)
 	configureSystemTray(a, w)
-	w.Resize(fyne.NewSize(1120, 720))
+	w.Resize(fyne.NewSize(1024, 660))
 	content, recordStartup := newMainView(w)
 	w.SetContent(content)
 	serveSingleInstance(instanceListener, w)