Motivation

• Provide the Unity client API a way to send RPCs to one or more specific clients instead of always broadcasting to the whole room.
• Preserve existing Rpc(...) broadcast behaviour while enabling targeted delivery without server protocol changes.

Description

• Added NetSyncManager.RpcTo(int targetClientNo, ...) and NetSyncManager.RpcTo(int[] targetClientNos, ...) to the Unity runtime to expose single/multi-target RPC sends via RpcTo.
• Extended RPCManager with SendTo(...), BuildTargetedFunctionName(...) and TryResolveTargetedFunctionName(...) to encode targets into the outgoing function name using an internal @target: prefix and to decode/resolve it on receive.
• Updated MessageProcessor to call RPCManager.TryResolveTargetedFunctionName(...) when processing MSG_RPC messages and to drop RPCs that are not addressed to the local client, while invoking local handlers with the original (decoded) function name.
• Implementation avoids server changes by encoding target metadata in the RPC function name and keeps existing Rpc(...) broadcast semantics unchanged.

Testing

• Ran repository structural/check command git diff --check and ensured no whitespace/diff-check issues were reported (success).
• Performed code inspection of changed files NetSyncManager.cs, RPCManager.cs, and MessageProcessor.cs to verify the send/receive target encoding and decoding logic was added.
• Note: No Unity Editor compile/play tests or Python unit tests were executed in this environment; manual verification in Unity Editor using Demo-01.unity or Debug Scene.unity with the server running is recommended.

Codex Task