test(render): foliage-wind receiver fallback guard asserts branch shape; cascade-0 publish covered (Campaign VM VM6 review 5 nits)

Round-5 narrow re-review of 754d59d9: APPROVE (verified to the SPIR-V
disassembly; shadows-on path proven opcode-identical). Four
non-blocking nits.

N1 (test robustness): T3 (ReceiverVertexShadersFallBackToThePlainLightDirectionWhenTheShadowFlagIsClear)
was satisfied by comment prose -- round 5's own explanatory comments
quote the exact plain-pipeline direction substring
("-uLights[i].dirAndRange.xyz, ... matched bit-for-bit"), so the
substring-only assertion passed even with the code mutated. Fixed:
comment lines are now stripped (new StripLineComments helper) before
any assertion, and a new ordered regex per shader asserts the exact
branch SHAPE -- shadowGatedOff ? -uLights[...] : normalize(uShadow...)
-- not just substring presence. Mutation-tested locally against the
rewritten test: (1) swapping the ternary's true/false operands --
FAILED (previously passed); (2) deleting the fallback entirely,
collapsing to the pre-round-5 buggy expression -- FAILED (previously
passed). Original file restored and reverified passing after each
mutation.

N2 (doc accuracy): "numerically the plain pipeline" overstated the
round-5 fix in three places (plan doc, mesh_atmospheric.vert,
terrain_atmospheric.vert). The direction expression is bit-for-bit;
the SUM is not, because the atmospheric shaders' split ambient+point
vs directional accumulation (and terrain's two varyings vs the plain
pipeline's one) reassociates float summation order by ~1 ulp -- which
is exactly the measured mean |Delta| 0.007 the coordinator's own
pixel-proof evidence already recorded (well under the 65 px noise
floor). All three rewritten to say the receiver "matches the plain
pipeline to within float summation-order rounding (measured mean
|Delta| 0.007 on the offline scene)."

N3 (coverage): RenderPrepared's own cascadeCount == 0 exit (the F2
fix) had no direct test even though RenderPrepared already has 8
direct call sites in this file. Added one: ResidentMaximumReachMeters
at/below CameraNearMeters, passed straight to RenderPrepared with an
otherwise-fully-valid environment (so the fitter, not the environment
gate, is what returns zero cascades), asserting IsBindableFor true /
IsValidFor false.

N4 (latent): RenderPrepared's OWN "if (!environment.ShouldRender)"
exit is a fourth bufferless-disabled path -- unreachable via Render
(whose own gate already validates ShouldRender first) but the same
shape, and RenderPrepared is called directly by tests and any future
caller. Took the preferred fix: publishes the disabled binding there
too, via the same helper, so every exit on a frame that draws the
world publishes when the pack's AtmosphericFrame is bound. Also made
EvaluateGateAndPublishDisabledBinding self-contained: it now resets
_currentFrameBinding to Disabled on its own entry instead of relying
on Render having done so first (idempotent with Render's own reset).

Regenerated SPIR-V: mesh_atmospheric.vert and terrain_atmospheric.vert
are comment-only changes (N2), so only the manifest's source hashes
changed -- compiled .spv bytes are unchanged, consistent with round 3's
precedent for comment-only shader edits.

Verify: Release build 0 warnings/0 errors. App hermetic-lane filter
6,055/0 failed. Full hermetic-filtered solution: 15,283/0 failed
across 15 projects.

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

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

@@ -721,7 +721,14 @@ plain-pipeline expression (`-uLights[i].dirAndRange.xyz` in
 `terrain_modern.vert`) instead of the shadow block's direction. Corrected
 statement: with the flag bit clear the receiver shaders take visibility
 1.0 AND fall back to the authored `uLights` direction (round 5), so a
-gated-off frame is numerically the plain pipeline. Wind is unaffected —
+gated-off frame matches the plain pipeline to within float summation-
+order rounding (review fix round 6, N2: "numerically the plain pipeline"
+overstated it — the direction expression is bit-for-bit, but the SUM is
+not, because the atmospheric fragment's split ambient+point vs
+directional accumulation reassociates the terms relative to the plain
+pipeline's single varying, and terrain's two separate varyings vs the
+plain pipeline's one do the same; measured mean |Δ| 0.007 on the offline
+scene, well under the apparatus's 65 px floor). Wind is unaffected —
 `foliage_wind.glsl` reads only the AtmosphericFrame half of set 3, never
 the shadow block.