Replaces inline docker:test script with scripts/docker-test.sh that:
- Detects and reports architecture (x86_64/arm64)
- Polls health endpoint with configurable timeout (60s)
- Verifies home page, health/live, health/ready endpoints
- Tests WebSocket endpoint reachability
- Proper cleanup on exit via trap
- Supports --skip-build flag for CI caching
Co-authored-by: ajnart <49837342+ajnart@users.noreply.github.com>
