Use python3 instead of unavailable python3.11 packages, drop apt step that failed on runner image, and replace buildx with docker build so the test step can run the built image.
Remove Python job containers so checkout@v4 can run (needs Node), install deps on ubuntu-latest for security-scan, and stop excluding README.md from Docker build context.
Switch HouseWatcherClient to public STOCK Act JSON (legacy housestockwatcher.com is down), add httpx/scikit-learn to pyproject, wire SMTP settings through Settings, fix get_session() as a context manager, and use savepoints in TradeLoader so one bad row does not roll back the batch.
