Every job now runs inside kryz-ci:latest via 'docker run' with volume
mounts. The image is built once per pipeline (with a cache check) instead
of every job redownloading Flutter + Android SDK + Java independently.
Before: ~40 min (each of 3-4 jobs downloads ~750MB of SDKs from scratch)
After (first run): ~25 min (single Docker build, then all jobs use cached image)
After (cached): ~5-8 min (image already on runner, jobs just docker run)
Changes:
- ci.yml: replace inline SDK setup in lint/test/build-android with
'docker run --rm -v ${PWD}:/workspace kryz-ci:latest' per step
- release.yml: same container strategy + fix auth token leak (was
hardcoded '***' instead of using $GITEA_TOKEN env var)
- ci.Dockerfile: add cleanup (rm /tmp, http cache) to shrink image size
- Net reduction: 3 files changed, -111 lines removed