ArWen 2.6.3

A fix release about what a fresh install does: aerosol-aware
forecasts run from a wheel install, upgrading gpuwm changes what runs,
and the Rust observation engine reads the grids the ingest path writes.

New:

• gpuwm doctor measures the install root against Windows' 260-character
  path ceiling, where a deep root on a box without long paths enabled
  makes every kernel source read fail as a missing file. Windows only,
  skipped by name elsewhere.
• The MPAS column-batch physics seam transports aerosol-aware Thompson
  (mp_physics = 28): WRF's eleven scalars, graupel receipts, the surface
  aerosol emission pair on the restart payload, and the scheme's own
  aerosol initialization at the seam's first microphysics call on the
  caller's state, so a batch that brings no aerosol data is a valid batch.

Fixed:

• 2.6.2 was tagged but never published: a test in the suite rewrote
  os.name process-wide, so every path operation raised on Linux and
  the release job died. 2.6.3 is that release plus the fix, and no
  2.6.2 artifacts reached PyPI.
• gpuwm fetch-tables stages CCN_ACTIVATE.BIN into the table root, so
  mp_physics = 28 runs from a wheel install. The command used to report
  the root complete and byte-valid while every aerosol-aware forecast
  died at its first microphysics step. It carries the classic set's pin.
• gpuwm fetch-tables --wif no longer lets the optional dataset leg
  cancel the mandatory one. Only --wif-only skips the coefficient
  tables, the exit code is the worst of the legs that ran, and a summary
  names each leg staged or refused.
• gpuwm fetch-tables --wif resolves QNWFA_QNIFA_SIGMA_MONTHLY.dat
  from the versioned release-assets base, honoring
  GPUWM_BRIDGE_ASSET_URL_BASE, where it used to answer 404. A refusal
  names the file, the URL and two ways to supply it.
• A bridge staged in ~/.gpuwm/bridges by an earlier release no longer
  reaches a door: every ladder checks it against this install's pins and
  re-fetches by default. Offline it refuses with the file, its revision
  and the replacing command; overrides, in-tree builds and wheel-shipped
  binaries are never judged.
• The Rust observation engine rw_obsgrid reads the windowed radar-grid
  layout natively. 2.6.1 made that layout what the ingest path writes
  while the engine still implemented the whole-domain one, so every
  freshly built grid was refused at the schema check. Older files stay
  readable.
• gpuwm doctor reports a skewed gpuwm-data companion as a blocking
  row carrying the exact pip line, rather than dying in an uncaught
  ImportError. The base-dependency line no longer prints ok over the
  pinned companion.
• The companion version lock compares PEP 440 public versions, so a
  wheel built with a local label accepts the gpuwm-data it was cut
  against, with a typeable remedy. A genuine release
  mismatch is still refused.
• The GPU preprocessing remedy names the certified CUDA pair instead of
  an uncertified extra. It states that such a box has no
  certified pair today and that the CPU backend runs there.
• A config's relative file references resolve from the config's own
  directory as well as the working directory, so a config that ships
  beside its data loads from anywhere. A value that already resolves is
  left byte for byte alone, so run fingerprints do not move.
• A host-only run no longer aborts at its first step boundary when CuPy
  is installed and every device is masked. The pool trim is an
  optimisation, so an unreachable pool now skips it instead of raising.
• Morrison deposition-freezing nucleation is bounded by the vapour excess
  over ice saturation. The unbounded term drove qv negative below about
  159 K, beyond a regional lid; it also engages between about 190 and
  213 K, which a cold tropopause under the default 50 hPa lid reaches.
  That divergence from WRF is declared and measured; no parity pin moved.
• The WPS_GEOG mirror carries the Noah-MP soilgrids archive, so a
  mesh-door gpuwm fetch-geog no longer falls from the default source to
  a 404. The publisher refuses to stage a pin table it cannot render.
• The two rw-mpas golden helper scripts compile again: a helper sat
  inside each module docstring, leaving both unterminated and the
  Rust tests' goldens impossible to regenerate. The whole-tree
  source scan now fails on a file it cannot parse.
• The RRTMGP cloud-fraction refusal names the scheme it refuses instead
  of citing only WRF line numbers, so the reader learns which arm is
  unsupported.