fix(ci): stop snapcraft resolving the root source-build recipe

The root snapcraft.yaml (source build, kept for Snap Store remote
builders) shadowed the staged snap/snapcraft.yaml dump recipe, so the
v2.0.0 snap job recompiled the entire workspace inside LXD and the
container OOM'd. Remove the root recipes from the CI working copy
before invoking snapcraft.

cc

.github/workflows/release-snap.yml

@@ -134,6 +134,12 @@ jobs:
           mkdir -p snap
           cp packaging/snap-slint/snapcraft.yaml snap/snapcraft.yaml
           sed -i "s/^version:.*/version: '${VER}'/" snap/snapcraft.yaml
+          # The repo ROOT also carries snapcraft.yaml (the SOURCE-build recipe
+          # for Snap Store remote builders) and snapcraft resolves it over
+          # snap/snapcraft.yaml — the v2.0.0 run recompiled the whole
+          # workspace inside LXD and OOM'd the container. Remove the root
+          # recipes from the CI working copy so only the dump recipe exists.
+          rm -f snapcraft.yaml .snapcraft.yaml
           echo "Built snap version: ${VER}"
           cat snap/snapcraft.yaml | head -20