feat(electron): bundle draw.io for offline support (#629)

* feat(electron): bundle draw.io for offline support

- Download draw.io static files during CI build (v29.3.5)
- Detect Electron and use local draw.io files instead of CDN
- Add offline=1 parameter to disable external service calls
- Skip /drawio path from i18n middleware redirect
- Add public/drawio/ to .gitignore (downloaded during build)

This allows the Electron app to work completely offline.

* chore: bump version to 0.4.12-beta.3 for offline test

* fix(electron): ad-hoc sign macOS app for bundled draw.io compatibility

* chore: bump version to 0.4.12-beta.4 for ad-hoc sign test

* fix(electron): disable electron-builder signing to use custom ad-hoc signing

* chore: bump version to 0.4.12-beta.5

electron/electron-builder.yml

@@ -37,10 +37,11 @@ mac:
       arch:
         - x64
         - arm64
-  hardenedRuntime: true
+  # Disable electron-builder's signing - we use custom ad-hoc signing in afterPack
+  # to properly sign nested bundles with --deep flag for bundled draw.io files
+  identity: null
+  hardenedRuntime: false
   gatekeeperAssess: false
-  entitlements: resources/entitlements.mac.plist
-  entitlementsInherit: resources/entitlements.mac.plist
 
 dmg:
   contents: