Fix ARM64 release cross build context

Run the Linux ARM64 cross build from the repository root and pass the backend manifest path explicitly.

This keeps the top-level themes directory available inside the cross container, so RustEmbed can resolve the backend theme assets through ../themes while compiling anycode-backend.

Author: vipmax

.github/workflows/release.yml

@@ -143,8 +143,8 @@ jobs:
         with:
           command: build
           target: aarch64-unknown-linux-musl
-          args: "--release"
-          working-directory: ./anycode-backend
+          args: "--release --manifest-path anycode-backend/Cargo.toml"
+          working-directory: .
 
       - name: Package as tar.gz
         working-directory: ./anycode-backend