fix(ci): use python yq syntax for flavours parsing

The runners have python yq (jq wrapper), not mikefarah/yq (Go).
Replace -o=json -I=0 with --compact-output which is the jq equivalent.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-release.yml

@@ -21,7 +21,7 @@ jobs:
           version="${TAG#v}"
           echo "version=${version}" >> "$GITHUB_OUTPUT"
           # Emit flavours as a JSON array for matrix consumption
-          flavours=$(yq -o=json -I=0 '.flavours' flavours.yml)
+          flavours=$(yq --compact-output '.flavours' flavours.yml)
           echo "flavours=${flavours}" >> "$GITHUB_OUTPUT"
         env:
           TAG: ${{ inputs.tag }}