fix(mcv): install python3 and build MCV image in example CI

The example image workflow pulled quay.io/gkm/mcv:latest before the
post-merge image build finished, so Triton cache key generation failed
without a python3 binary. Build mcv-minimal from the checkout instead
and install python3 explicitly in runtime image stages.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: 2 people

.github/workflows/mcv-build-example-images.yml

@@ -61,8 +61,13 @@ jobs:
           registry: ${{ env.REGISTRY }}
           username: ${{ secrets.QUAY_USERNAME }}
           password: ${{ secrets.QUAY_PASSWORD }}
-      - name: Pull MCV builder image
-        run: podman pull quay.io/gkm/mcv:latest
+      - name: Build MCV builder image from checkout
+        run: |
+          podman build \
+            --platform linux/amd64 \
+            --target mcv-minimal \
+            -t quay.io/gkm/mcv:latest \
+            -f mcv/images/Containerfile .
 
       - name: Build images inside MCV container and load to host
         env:

mcv/images/Containerfile

@@ -63,6 +63,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     netavark aardvark-dns \
     fuse-overlayfs fuse3 \
     hwdata \
+    python3 \
     python3-setuptools \
     python3-wheel \
  && rm -rf /var/lib/apt/lists/*
@@ -155,6 +156,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     netavark aardvark-dns \
     fuse-overlayfs fuse3 \
     hwdata \
+    python3 \
     python3-setuptools \
     python3-wheel \
  && rm -rf /var/lib/apt/lists/*
@@ -202,6 +204,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     netavark aardvark-dns \
     fuse-overlayfs fuse3 \
     hwdata \
+    python3 \
     python3-setuptools \
     python3-wheel \
  && rm -rf /var/lib/apt/lists/*