fix(ci): use cargo-zigbuild for cross-compilation in publish workflow

Replace BUILD_FROM_SOURCE=1 (QEMU emulation, 45+ min) with native
cross-compilation using cargo-zigbuild via stage-prebuilt-binaries.sh.
Docker now just copies prebuilt binaries (seconds) instead of compiling
Rust from source under QEMU emulation.

Assisted-By: Claude (Anthropic AI) <noreply@anthropic.com>
Signed-off-by: Paolo Dettori <dettori@us.ibm.com>

Author: pdettori

.github/workflows/publish.yml

@@ -18,7 +18,7 @@ env:
 jobs:
   build-and-push:
     runs-on: ubuntu-latest
-    timeout-minutes: 90
+    timeout-minutes: 45
 
     permissions:
       contents: read
@@ -28,6 +28,23 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6
 
+      - uses: jdx/mise-action@v2
+
+      - name: Add Rust targets
+        run: |
+          rustup target add x86_64-unknown-linux-gnu
+          rustup target add aarch64-unknown-linux-gnu
+
+      - name: Cache Rust target and registry
+        uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: publish-binaries
+
+      - name: Cross-compile gateway for amd64 and arm64
+        env:
+          DOCKER_PLATFORM: linux/amd64,linux/arm64
+        run: tasks/scripts/stage-prebuilt-binaries.sh gateway
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a  # v4.0.0
 
@@ -77,15 +94,14 @@ jobs:
           target: gateway
           push: true
           platforms: linux/amd64,linux/arm64
-          build-args: BUILD_FROM_SOURCE=1
           tags: ${{ steps.meta_retry.outputs.tags || steps.meta.outputs.tags }}
           labels: ${{ steps.meta_retry.outputs.labels || steps.meta.outputs.labels }}
           cache-from: type=gha,scope=gateway
           cache-to: type=gha,scope=gateway,mode=max
 
   build-and-push-supervisor:
     runs-on: ubuntu-latest
-    timeout-minutes: 90
+    timeout-minutes: 45
 
     permissions:
       contents: read
@@ -95,6 +111,23 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6
 
+      - uses: jdx/mise-action@v2
+
+      - name: Add Rust targets
+        run: |
+          rustup target add x86_64-unknown-linux-gnu
+          rustup target add aarch64-unknown-linux-gnu
+
+      - name: Cache Rust target and registry
+        uses: Swatinem/rust-cache@v2
+        with:
+          shared-key: publish-binaries
+
+      - name: Cross-compile supervisor for amd64 and arm64
+        env:
+          DOCKER_PLATFORM: linux/amd64,linux/arm64
+        run: tasks/scripts/stage-prebuilt-binaries.sh supervisor
+
       - name: Set up QEMU
         uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a  # v4.0.0
 
@@ -144,7 +177,6 @@ jobs:
           target: supervisor
           push: true
           platforms: linux/amd64,linux/arm64
-          build-args: BUILD_FROM_SOURCE=1
           tags: ${{ steps.meta_retry.outputs.tags || steps.meta.outputs.tags }}
           labels: ${{ steps.meta_retry.outputs.labels || steps.meta.outputs.labels }}
           cache-from: type=gha,scope=supervisor