feat(styling): expand the weather/atmospheric preset library with CAMS composition and operational fields

[MAfarrag]

Context

weather_presets.json holds shortName-keyed atmospheric presets (Magics-derived, Apache-2.0) that map ECMWF-style
meteorological variables onto banded colour scales. PR #275 grows this library from 84 to 112 presets — the
+28 genuinely new on this branch vs main — covering CAMS atmospheric-composition levels and a long tail of
operational meteorology/hydrology fields.

Problem / Current Behaviour

The weather preset set covered common surface fields but was missing:

• CAMS atmospheric-composition presets at pressure levels (carbon monoxide / methane at 500/700/850 hPa, etc.),
• operational long-tail fields: cloud base/ceiling, sea-ice, snow/soil hydrology, vorticity/divergence at levels,
  upper-air temperature and wind-speed at standard pressure levels, visibility, river discharge, and more.

Affected locations

File	Symbol	Notes
src/cleopatra/styling/data/weather_presets.json	presets (84 -> 112)	+28 shortName presets
src/cleopatra/styling/colors.py	_load_presets, resolve_style_norm	consumes the added banded/levelled presets
tools/build_weather_presets.py	maintainer-only build tool (local, untracked)	fetch + bake

Motivation Example

from cleopatra.glyphs.gridded.array_glyph import ArrayGlyph
from cleopatra.styling.params import DataStyle

ArrayGlyph(co_700).plot(data_style=DataStyle(style="carbon_monoxide_700hpa"))
ArrayGlyph(u250).plot(data_style=DataStyle(style="wind_speed_250hpa"))
ArrayGlyph(sic).plot(data_style=DataStyle(style="sea_ice_cover"))

Delivered presets (+28 vs main)

cloud_base_height, cloud_ceiling, divergence_1000hpa, freezing_rain, potential_vorticity_315k,
relative_humidity_1000hpa, relative_vorticity_700hpa, relative_vorticity_850hpa, river_discharge, sea_ice_cover,
snow_water_equivalent, soil_wetness_index, surface_net_solar_radiation, temperature_250hpa, temperature_3hpa,
temperature_500hpa, temperature_925hpa, total_precipitation_rate, total_runoff_water_equivalent,
vertical_velocity_700hpa, visibility, wet_bulb_potential_temperature_850hpa, wind_speed_200hpa, wind_speed_250hpa,
wind_speed_300hpa, wind_speed_500hpa, wind_speed_800hpa, wind_speed_925hpa

Out of Scope

• Colour-map palettes (scientific / terrain / radar) — tracked separately.
• Any new runtime dependency — presets are vendored JSON.

Effort Estimate

Size: M
Rationale: sourcing, schema-fitting, and validating 28 additional banded/levelled presets plus gallery coverage.

Definition of Done

• 28 CAMS-composition + operational presets added to weather_presets.json (84 -> 112) under the v2 schema
• each resolves through resolve_style_norm (banded / levelled scales render with a correct colorbar)
• gallery notebooks: cams_* (4), operational_weather_gallery
• neutral source naming - no ecmwf / earthkit in filenames, docstrings, identifiers, or data
• all existing tests continue to pass