stream_queue_check.py: batch --playlist mode, per-stream JSON via --out-dir, TTY-aware summary vs JSON, HLS health judged by rebuffers (TS by stall), 120s default duration, --tolerance/--stall-timeout. New stream_graph.py renders the checker JSON as dependency-free SVG charts (per-stream + --combined comparison, unique colour per stream). Both moved under tools/stream-check/ with a README; tools/README.md and docs/en updated.
