Finish JerryScript Entity/Scene wiring; remove JSON serialize/deserialize

Register Entity, the generic Component wrapper, and Scene as JerryScript
classes (modulelist.c ties them together, plus their .d.ts stubs), so
scenes/entities can be built from script going forward instead of the
JSON scene format.

With scripting now the intended authoring path, drop the JSON
serialize/deserialize machinery entirely: componentdefinition_t's
serialize/deserialize callbacks, every component's *Serialize/
*Deserialize function, entitySerialize/entityDeserialize,
sceneSerialize/sceneDeserialize, and the "prefabs/<name>.json"/
"scenes/<name>.json" asset fallback in entityPrefabResolveAndApply/
scenePrefabResolveAndApply (C-coded prefabs only now). physicsshape.c
and its test are removed outright since they only existed for this.
game.c's test scene now comes from the existing overworldSceneCreate()
C builder instead of loading the now-deleted assets/scenes/test.json.

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

assets/scenes/test.json

@@ -1,66 +0,0 @@
-{
-  "extend": "OVERWORLDSCENE",
-  "entities": [
-    {
-      "components": [
-        { "type": "POSITION", "x": 0, "y": 1, "z": 0, "parent": "camera" }
-      ]
-    },
-    {
-      "name": "testArea",
-      "components": [
-        { "type": "POSITION", "x": 2, "y": 1, "z": 0 },
-        {
-          "type": "TRIGGER",
-          "collideMask": 2,
-          "shape": {
-            "type": "CUBE",
-            "halfExtentX": 1.5, "halfExtentY": 1.5, "halfExtentZ": 1.5
-          }
-        }
-      ]
-    },
-    {
-      "name": "npc",
-      "components": [
-        { "type": "POSITION", "x": -3, "y": 1, "z": 0 },
-        {
-          "type": "RENDERABLE",
-          "renderType": "SHADER_MATERIAL",
-          "priority": 0,
-          "shaderType": "UNLIT",
-          "color": { "r": 80, "g": 255, "b": 120, "a": 255 },
-          "displayState": { "cull": false, "depthTest": true, "blend": false }
-        },
-        { "type": "PHYSICS", "bodyType": "STATIC" },
-        { "type": "INTERACTABLE", "kind": "ITEM_PICKUP", "pickupId": 1 }
-      ]
-    },
-    {
-      "components": [
-        {
-          "type": "POSITION",
-          "x": 0, "y": -0.1, "z": 0,
-          "scale": { "x": 20, "y": 0.2, "z": 20 }
-        },
-        {
-          "type": "RENDERABLE",
-          "renderType": "SHADER_MATERIAL",
-          "priority": 0,
-          "shaderType": "UNLIT",
-          "color": { "r": 128, "g": 128, "b": 128, "a": 255 },
-          "displayState": { "cull": false, "depthTest": true, "blend": false }
-        },
-        {
-          "type": "PHYSICS",
-          "bodyType": "STATIC",
-          "shape": {
-            "type": "PLANE",
-            "normalX": 0, "normalY": 1, "normalZ": 0,
-            "distance": 0
-          }
-        }
-      ]
-    }
-  ]
-}