fix(menu): make View → Zoom In accept the unshifted Ctrl+= key (#55)

The app relied on Electron's default application menu, whose View → Zoom In
binds only `CommandOrControl+Plus`. On US / most keyboard layouts "+" is the
shifted form of `=`, so pressing Ctrl with the unshifted +/= key sends Ctrl+=
and nothing happened — while Zoom Out (`Ctrl+-`, no Shift) worked, making zoom
feel half-broken.

Install an explicit application menu that mirrors Electron's default via
role-based submenus and hand-builds only View, where Zoom In also accepts
`Ctrl+=` and numpad `+` (hidden sibling items keep `Ctrl+Shift+=` and numpad
working). Strictly additive — no other menu behaviour changes.


Claude-Session: https://claude.ai/code/session_01QbexxfTt8q2tAn436MqGWF

Co-authored-by: ChrisBeWithYou <chris@rifflarr.local>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

src/main/main.ts

@@ -124,6 +124,7 @@ import { initPluginManager } from './plugin-manager';
 import { initSoundfontManager, getDesktopConfig, setDesktopConfig } from './soundfont-manager';
 import * as updateManager from './update-manager';
 import type { UpdateChannel } from './update-manager';
+import { installAppMenu } from './app-menu';
 
 // Linux: enable Chromium's PipeWire capturer feature so getUserMedia can see
 // audio devices on PipeWire-only distros (Fedora 36+, recent Ubuntu, Arch).
@@ -1026,6 +1027,10 @@ async function startup(): Promise<void> {
     // Create the main window
     createWindow(port);
 
+    // Install our application menu (replaces Electron's default so View →
+    // Zoom In also accepts the unshifted Ctrl+= key — see app-menu.ts).
+    installAppMenu();
+
     // Register file picker IPC
     ipcMain.handle('dialog:pickFile', async (_event, filters?: { name: string; extensions: string[] }[]) => {
         if (!mainWindow) return null;