fix(get_gameobject): prevent MCP crash on oversized responses (#134)

Recursive GameObject serialization had no depth or byte limits, so deep
prefab trees could produce JSON larger than the MCP framework's 15MB
response cap and silently drop the WebSocket connection.

Add three optional scoping params (default maxDepth=2, includeComponents,
includeComponentProperties) and a 5MB byte-cap backstop inside the
serializer. When either limit is hit, the node carries a _truncated
marker with a reason and hint so the caller can re-query a narrower
subtree instead of losing the connection.