Art/Fix: A0 gate pass — death-pose lock, off-palette drift, lighting debris

Found by running the A0 style-proof against the SHIPPING scene instead of
ArtStaging (which judges static glTF bakes on an import shader, with zero
SkinnedMeshRenderers and no Animator — it cannot answer "does the game look
like this").

Player-facing bugs fixed:

- AC_PlayerTopDown/AC_EnemyTopDown "Death" had ZERO outgoing transitions.
  Any State enters on IsDead and nothing ever leaves. The player ghost is a
  persistent entity, so its Rukhanka animator never resets: once you died you
  rendered sprawled on the seabed permanently — sim fully respawned, moving and
  fighting, visually a corpse. Added Death -> Idle on (IsDead == false).

- AmbientMotionSystem drift was still the deleted biome system: key 0 =
  "meadow", MeadowMoteColor (0.62, 0.85, 0.60) = GREEN motes, 600 of them in a
  36x7x24 box following the camera — the most off-palette thing in the frame.
  Its x>500 region probe pointed at space now holding zero renderers. Collapsed
  to one cold marine particulate; dropped the 4 dead mote colours + AridWind.

- FeedbackFx.MakeParticleMaterial built Sprites/Default with NO texture, so
  every procedural particle rendered as a hard SQUARE. Added a procedural soft
  dot (no Resources.Load — build-stripped; asset-free presentation is the rule).

- Game.unity carried a stock Unity "Directional Light" (warm-WHITE, 1.05, Soft)
  outranking KeyWarm as a second competing shadow caster, plus 6 orphaned
  LandmarkLights — four at x=1030/1530 lighting a kilometre of empty water, two
  with no renderer within 12u, two of them purple. All 7 deleted. Added RimCold
  for silhouette separation; key:fill set to the tuned 3.9:1; WarmPool -> Soft.

ArtStaging (kept as a lighting lab): KeyWarm 0.15 -> 0.85 — it was the only
shadow-caster yet sat BELOW GloamFill 0.22, which destroys form by definition
and is what read as "flat". StagingAmbiance was attached to nothing and its
flora wiring searched for a Game.unity parent, which is what read as "static";
it also force-played the combat one-shot pool, now restricted to looping
emitters. Flicker raised to a measured x2.11 cold swing vs x1.03 warm.

304/304 EditMode green; death-recovery, palette and particulate all verified
live in Game.unity Play.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Assets/_Project/Scripts/Client/Presentation/FeedbackFx.cs

@@ -33,6 +33,38 @@ namespace ProjectM.Client
             return clip;
         }
 
+        static Texture2D s_softDot;
+
+        /// <summary>
+        /// Sprites/Default with NO texture renders hard SQUARES — which is what the ambient drift was painting
+        /// across the seabed (found at the 2026-08-07 A0 gate). Build the dot procedurally instead of referencing
+        /// an asset: runtime Resources.Load is stripped from player builds, and asset-free presentation is the
+        /// house rule. Self-healing across fast-enter-playmode — a destroyed texture compares == null and rebuilds.
+        /// </summary>
+        public static Texture2D SoftDot()
+        {
+            if (s_softDot != null) return s_softDot;
+            const int N = 32;
+            var t = new Texture2D(N, N, TextureFormat.RGBA32, false)
+            {
+                name = "T_SoftDotProc",
+                wrapMode = TextureWrapMode.Clamp
+            };
+            for (int y = 0; y < N; y++)
+            {
+                for (int x = 0; x < N; x++)
+                {
+                    float dx = (x + 0.5f) / N * 2f - 1f;
+                    float dy = (y + 0.5f) / N * 2f - 1f;
+                    float a = Mathf.Clamp01(1f - Mathf.Sqrt(dx * dx + dy * dy));
+                    t.SetPixel(x, y, new Color(1f, 1f, 1f, a * a));   // squared = softer falloff
+                }
+            }
+            t.Apply();
+            s_softDot = t;
+            return t;
+        }
+
         public static Material MakeParticleMaterial(string name = "FeedbackParticle")
         {
             // Sprites/Default is an always-included transparent vertex-coloured shader (reliable billboarded sparks;
@@ -40,7 +72,7 @@ namespace ProjectM.Client
             Shader sh = Shader.Find("Sprites/Default");
             if (sh == null) sh = Shader.Find("Universal Render Pipeline/Particles/Unlit");
             if (sh == null) sh = Shader.Find("Unlit/Color");
-            return new Material(sh) { name = name };
+            return new Material(sh) { name = name, mainTexture = SoftDot() };
         }
 
         public static ParticleSystem MakeBurst(Transform parent, string name, Material mat, Color color,