fix(04-00): rename particle assets to PascalCase per Hytale validator

Server WARN: "Asset key 'chain_spark' has incorrect format! Expected: 'Chain_Spark'".
Hytale validator derives expected asset key from filename via PascalCase
normalization. Renamed all three files + internal SpawnerId + Texture refs.

This contradicts the GravityFlip snake_case rule for Particles specifically —
filename casing IS the asset key.

src/main/resources/Server/Particles/Chain_Spark.particlespawner

@@ -8,7 +8,7 @@
   "ParticleLifeSpan": { "Min": 0.3, "Max": 0.5 },
   "SpawnRate": { "Min": 50.0, "Max": 50.0 },
   "Particle": {
-    "Texture": "Particles/chain_spark.png",
+    "Texture": "Particles/Chain_Spark.png",
     "FrameSize": { "Width": 4, "Height": 4 },
     "SoftParticles": "Enable",
     "SoftParticlesFadeFactor": 1.0,

src/main/resources/Server/Particles/Chain_Spark.particlesystem

@@ -4,7 +4,7 @@
   "BoundingRadius": 1.0,
   "Spawners": [
     {
-      "SpawnerId": "chain_spark"
+      "SpawnerId": "Chain_Spark"
     }
   ]
 }