feat(electron): set window minimum size (closes #994)

src/services/window.ts

@@ -156,6 +156,8 @@ async function createMainWindow(app: App) {
         y: mainWindowState.y,
         width: mainWindowState.width,
         height: mainWindowState.height,
+        minWidth: 500,
+        minHeight: 400,
         title: "TriliumNext Notes",
         webPreferences: {
             nodeIntegration: true,