fix: resize macOS app icon to fill full squircle frame

The icon was designed in iOS style with baked-in rounded corners and
transparent padding, causing it to appear small inside macOS Big Sur+
squircle mask. Scaled content ~18% larger and filled transparent corners
with matching dark purple background. Regenerated .icns with all sizes.

Bump version to 0.12.1.

Author: AnasProgrammer2

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "netcopilot",
-  "version": "0.12.0",
+  "version": "0.12.1",
   "description": "NetCopilot – AI-powered SSH/Telnet terminal for network engineers",
   "main": "./out/main/index.js",
   "author": {