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

proxy.ts

@@ -31,6 +31,7 @@ export function proxy(request: NextRequest) {
     if (
         pathname.startsWith("/api/") ||
         pathname.startsWith("/_next/") ||
+        pathname.startsWith("/drawio") ||
         pathname.includes("/favicon") ||
         /\.(.*)$/.test(pathname)
     ) {