ArWen 2.5.6

ArWen 2.5.6

2.5.5 was tagged but never published: the public snapshot commit lost four
vendored Rust build files to the build-directory ignore rule, so the release
cut could not build the bridges and nothing reached PyPI. The tag stays where
it is, because tags here are forward-only. Everything 2.5.5 carried ships
here.

A run that narrates its own life, and radiation that fits the card.

New:

• Nest lifecycle in the per-step stream (schema gpuwm.step-log/v3):
  nest_spawned, nest_retired, nest_rearmed, nest_moved, containment_moved
  and track_fix, each with the domain, its step count, the valid time and
  the position. v1 and v2 streams replay unchanged.
• The delivered render layout gains an episode segment
  (out/domain/episode-NNN/product/valid-day), so two lives of one nest
  publishing the same valid time no longer overwrite each other.
  Non-episodic runs keep their exact paths.
• gpuwm branch: a what-if door that seeds a new run from an existing
  checkpoint, with --set overrides. A pinned setting is refused by name
  with the changeable list in the sentence.
• The MPAS seam publishes refl10cm and q2 in the default history stream,
  computed inside the history step's own microphysics call, and the
  rw-mpas converter maps REFL_10CM and Q2. Reflectivity products read the
  model's own field instead of a hydrometeor fallback.

Fixed:

• The vortex track CSV is tail-safe while the run writes it: every row
  reaches the OS at its newline, and the header is readable before the
  first fix.
• The legacy-RRTMG batch chunk width sizes itself to the device it runs
  on instead of paying the largest card's workspace everywhere. Results
  are byte-identical at any width. Measured 2026-08-24 on an RTX 5070 Ti
  (gpuwm-hex x1.40962): peak process memory 6,724.0 to 5,604.0 MiB.
• Grell-Freitas column arrays leave the fully-resident kernel frame on
  the MPAS column-batch path, shrinking the port's fixed device
  reservation.
• Offline downscaling from a WSM6 parent works; the transport table
  refused a scheme its own contract admits.