Set geo mirror and created a nighly runner to build the ISO

.github/workflows/nightly-build.yml

@@ -0,0 +1,37 @@
+name: Nightly ISO Build
+
+on:
+  schedule:
+    - cron: '1 0 * * *'  # Daily at 00:01 UTC
+  workflow_dispatch:  # Allow manual triggering
+
+jobs:
+  build-iso:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+      
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+      
+    - name: Build ISO in Arch Linux container
+      run: |
+        docker run --rm \
+          --privileged \
+          -v "${{ github.workspace }}:/workspace" \
+          -w /workspace \
+          archlinux:latest \
+          bash -c "
+            pacman -Syu --noconfirm && \
+            chmod +x build_iso.sh && \
+            ./build_iso.sh
+          "
+    
+    - name: Upload ISO artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: omarchy-iso-${{ github.run_number }}
+        path: out/*.iso
+        retention-days: 30