Downgrade to Electron 38.7 and simplify entitlements for macOS performance

- Downgrade from Electron 40.0.0 to 38.6.0 (installed 38.7.2)
- Remove unnecessary entitlements that may cause extra macOS security validation:
  - com.apple.security.cs.allow-unsigned-executable-memory
  - com.apple.security.cs.disable-library-validation
  - com.apple.security.cs.disable-executable-page-protection
- Keep only required entitlements:
  - com.apple.security.cs.allow-jit (required for V8 JavaScript)
  - com.apple.security.automation.apple-events (required for automation)

These changes aim to fix slow click performance on macOS 26 Tahoe by:
1. Using more stable Electron version with macOS Tahoe fixes
2. Reducing security validation overhead on user interactions

Author: RobbieTheWagner

electron-app/src/entitlements.plist

@@ -4,12 +4,6 @@
   <dict>
     <key>com.apple.security.cs.allow-jit</key>
     <true/>
-    <key>com.apple.security.cs.allow-unsigned-executable-memory</key>
-    <true/>
-    <key>com.apple.security.cs.disable-library-validation</key>
-    <true/>
-    <key>com.apple.security.cs.disable-executable-page-protection</key>
-    <true/>
     <key>com.apple.security.automation.apple-events</key>
     <true/>
   </dict>

package.json

@@ -140,7 +140,7 @@
     "broccoli-asset-rev": "^3.0.0",
     "concurrently": "^9.2.1",
     "cross-env": "^10.1.0",
-    "electron": "^40.0.0",
+    "electron": "^38.6.0",
     "ember-auto-import": "^2.12.0",
     "ember-cli": "^6.10.0",
     "ember-cli-babel": "^8.2.0",