fix(render): foliage wind keys on the DAT-classified WeatherKind, not the day-group index (Campaign VM VM6)

FoliageWindByDayGroup / FoliageWindDayGroupPoint(int ActiveDayGroup, ...)
becomes FoliageWindByWeather / FoliageWindWeatherPoint(string WeatherKind,
...) in AtmospherePolicyDeclaration (Plugin.Abstractions is BCL-only, so
the key is the exact member name of AcDream.Core.World.WeatherKind rather
than the enum itself). The raw activeDayGroup index carries no weather
meaning by itself; WeatherState.cs already classifies each day group's
authored DAT name into one of five real weather kinds, and that fact was
already threaded through AtmosphericFrameInputs.Weather / uAtmosphereWeather.x
— this reuses it instead of guessing an index-to-category mapping.

Built-in table (BuiltInAtmosphericRenderPack.AtmospherePolicy()): Clear
0.25/0.15, Overcast 0.60/0.35, Rain 0.85/0.60, Snow 0.35/0.20, Storm
1.00/0.75 — all five WeatherKind members declared, the invented "Cloudy"
row dropped. RenderPackAtmospherePolicyEvaluation.FoliageWind now takes a
WeatherKind and matches by weather.ToString() (ordinal) against each
declared point's name; a kind absent from the table falls back to the
declared Clear row, then to (0,0) if Clear itself is undeclared. The
delta-seconds EMA interpolation (EaseTowardTarget) is unchanged.
AtmosphericPostProcessGraph.ResolveFoliageWind and its two callers
(RenderPostProcess via inputs.Weather; RenderDirectionalShadows via
foundation.Atmosphere.Kind) now pass WeatherKind instead of the day-group
int.

RenderPackValidation.ValidateAtmosphere (runs for every pack declaring an
AtmospherePolicy, not gated to Tier2/shadow packs) now rejects an unknown
or non-exact-case weather-kind name and a repeated kind, mirroring the
existing ActiveDayGroupMultiplier duplicate-key check.

Tests: RenderPackAtmospherePolicyEvaluationTests rewritten for the
kind-keyed API (all five kinds resolve to their declared row, an unlisted
kind falls back to Clear, ordinal exact-case matching, null-table
handling); RenderPackSpirvValidatorTests gains four descriptor-validation
cases (unknown name, wrong case, duplicate kind, the five-kind table
accepted); AtmosphericPostProcessGraphTests' three foliage-wind cases now
select WeatherKind.Storm via `with` instead of an assumed day-group index.

Spot-check (per the coordinator's ask, not changed here): yes —
ActiveDayGroupMultiplier / EvaluateDayGroupPolicy (pre-existing, Campaign
AR/VM3-era — BuiltInAtmosphericRenderPack.AtmospherePolicy()'s three rows
`new ActiveDayGroupMultiplier(0, 1.0), (1, 0.35), (2, 0.20)`) key the
sun-ray/shadow/volumetric day-group strength multiplier by the same raw
activeDayGroup index with an undocumented assumed meaning (0=brightest ...
2=dimmest), the identical class of issue this commit fixes for foliage
wind. Left unchanged per instruction; flagging for the coordinator to file.

Full solution Debug and Release builds green. App hermetic filter
6024/6026 — the same 2 pre-existing failures as VM6a/VM6b. Both were
re-run in isolation per the verification ask: both still fail alone (not
a load-flake in this environment) — confirmed via git stash earlier this
session that both already fail on the unmodified pre-VM6 baseline, so
they are pre-existing and unrelated to this change. Core.Tests hermetic
4697/4697. RenderPackValidator.Tests 30/30. No shader/spv changes in this
commit (pure C#/docs fix).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/plans/2026-08-22-visualmaster-campaign.md

@@ -474,18 +474,26 @@ direction to read, and the register row says so.
 
 ### VM6 outcome (implementation landed 2026-08-22; owner visual gate outstanding)
 
-Two commits (VM6a shader ABI v2 plumbing, VM6b the feature) shipped the exact
-design above. Settings (`BuiltInAtmosphericRenderPack.Settings()`):
-`wind-enabled` (bool, default on), `wind-strength` (0–2×, default 1.0),
-`wind-direction-degrees` (0–360°, default 225 — no authored retail wind
-direction exists to read), `wind-lean-metres` (default 0.25),
-`wind-branch-metres` (default 0.15), `wind-flutter-metres` (default 0.05,
-forced to 0 on the Low preset), `wind-canopy-height-metres` (default 8). The
-Clear/Cloudy/Overcast/Rainy mean/gust rows live in
-`AtmospherePolicyDeclaration.FoliageWindByDayGroup`, keyed by the SAME
-day-group index convention `ActiveDayGroupMultipliers` already established
-two lines above it in `AtmosphericPolicy()` (0 Clear / 1 Cloudy / 2 Overcast;
-index 3 Rainy is new). Classification bits live in
+Two commits (VM6a shader ABI v2 plumbing, VM6b the feature) shipped the
+design above; a same-day fix-round commit corrected the weather-table key.
+Settings (`BuiltInAtmosphericRenderPack.Settings()`): `wind-enabled` (bool,
+default on), `wind-strength` (0–2×, default 1.0), `wind-direction-degrees`
+(0–360°, default 225 — no authored retail wind direction exists to read),
+`wind-lean-metres` (default 0.25), `wind-branch-metres` (default 0.15),
+`wind-flutter-metres` (default 0.05, forced to 0 on the Low preset),
+`wind-canopy-height-metres` (default 8). The mean/gust rows live in
+`AtmospherePolicyDeclaration.FoliageWindByWeather`, keyed by NAME
+(`FoliageWindWeatherPoint.WeatherKind`, an exact ordinal match against
+`AcDream.Core.World.WeatherKind`'s member names — `Clear` 0.25/0.15,
+`Overcast` 0.60/0.35, `Rain` 0.85/0.60, `Snow` 0.35/0.20, `Storm` 1.00/0.75),
+not the raw `activeDayGroup` index the original design used: the index
+carries no weather meaning by itself, and `WeatherState.cs` already
+classifies each day group's authored DAT name into one of these five real
+kinds — the same fact `AtmosphericFrameInputs.Weather` /
+`uAtmosphereWeather.x` already threads through the frame, reused here
+instead of re-guessed. `RenderPackAtmospherePolicyEvaluation.FoliageWind`
+matches by `weather.ToString()` and falls back to the declared Clear row for
+an unlisted kind. Classification bits live in
 `FoliageWindClassification` (`AcDream.App.Rendering.Wb`): bit 1 (`0x2`)
 cutout foliage, bit 2 (`0x4`) trunk, computed once per (entity, subset) in
 `WbDrawDispatcher.ClassifyBatches` (world receiver) and