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

.github/workflows/electron-release.yml

@@ -34,6 +34,15 @@ jobs:
           node-version: 24
           cache: "npm"
 
+      - name: Download draw.io static files for offline use
+        run: |
+          rm -rf public/drawio
+          git clone --depth 1 --branch v29.3.5 https://github.com/jgraph/drawio.git /tmp/drawio
+          mkdir -p public/drawio
+          cp -r /tmp/drawio/src/main/webapp/* public/drawio/
+          rm -rf public/drawio/WEB-INF
+          rm -rf public/drawio/META-INF
+
       - name: Install dependencies
         run: npm install
 
@@ -57,6 +66,16 @@ jobs:
           node-version: 24
           cache: "npm"
 
+      - name: Download draw.io static files for offline use
+        shell: bash
+        run: |
+          rm -rf public/drawio
+          git clone --depth 1 --branch v29.3.5 https://github.com/jgraph/drawio.git /tmp/drawio
+          mkdir -p public/drawio
+          cp -r /tmp/drawio/src/main/webapp/* public/drawio/
+          rm -rf public/drawio/WEB-INF
+          rm -rf public/drawio/META-INF
+
       - name: Install dependencies
         run: npm install