Soak test gaps: 200-file fixture, Windows, snapshots, ASan build

- Test project: 377 files (80 Python + 40 Go + 40 TSX + configs)
  instead of 5 files. RSS baseline now ~47MB (real workload).
- Snapshots every 10s (was 30s) — 7+ data points in 1-min run.
- Reindex every 2min compressed (was 5min) — more cycles per run.
- heap_committed fallback: use RSS when mimalloc reports 0.
- Windows soak: added to quick soak matrix (MSYS2 + python3 + git).
- ASan soak: builds with -fsanitize=address (was building release).
- Collect snapshot with single python3 call (was 6 separate calls).