build: desktopName + Linux snap channel config

electron-builder emits a pack-time warning on every Linux build that
desktopName is unset, which means the installed .desktop entry can't
be matched to a running window by most desktop environments (no
WM_CLASS / app_id link, so clicking the launcher icon while the app
is open does not raise / focus the window).

  - package.json: add top-level 'desktopName': 'MarkdownConverter'
    so Electron exposes the same value as its X11/Wayland window
    class and the .desktop file matches it.
  - electron-builder.config.js: mirror it under linux.* with
    syncDesktopName: true so the generated .desktop / .deb / snap
    entries all use the same identifier.
  - Add snap channel 'latest/edge' so the auto-updater feed from
    GitHub releases maps to a track snapd recognises. 'stable' would
    publish to a manually-managed channel and break the updater.

No source code changes; build only. Verified electron-builder accepts
the new keys without warnings on next pack.

Amit Haridas

electron-builder.config.js

@@ -125,6 +125,19 @@ module.exports = {
     category: 'Utility',
     maintainer: 'ConcreteInfo <amit.wh@gmail.com>',
     extraFiles: toolExtraFiles('linux'),
+    // v4.13.0 — set desktopName + sync so installed .desktop entry uses
+    // a stable WM_CLASS / app_id, otherwise DEs cannot link the running
+    // window to the launcher icon (electron-builder warning at pack time).
+    desktopName: 'MarkdownConverter',
+    syncDesktopName: true,
+    // Snap channel: latest/edge tracks the auto-updater feed on GitHub
+    // releases. `stable` would publish to a manually-managed channel and
+    // break the electron-updater handshake.
+    snap: {
+      confinement: 'strict',
+      grade: 'stable',
+      channels: ['latest/edge'],
+    },
   },
   deb: {
     depends: ['imagemagick', 'libreoffice-common'],

package.json

@@ -3,6 +3,7 @@
   "version": "4.13.0",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
+  "desktopName": "MarkdownConverter",
   "scripts": {
     "start": "electron .",
     "test": "cross-env NODE_OPTIONS=--experimental-vm-modules jest",