Document command payload resolution behavior

[invictvs-k]

Summary

• document the supported payload shapes handled by ResolveCommandTarget
• clarify the intent for keeping command payload type checks localized to the helper

Testing

• Not run (dotnet CLI not available in container)

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https://chatgpt.com/codex/tasks/task_e_68f30ef788c0832e8b94ef5ab7c4dbd5

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid trusting client owner_user_id as authenticated identity

The join handler assigns userId from the incoming payload when the caller is unauthenticated (userId ??= entity.OwnerUserId). Permission checks such as CanSendCommand and CanDirectMessage rely on session.UserId to enforce owner-only restrictions. A client can therefore join without authentication, set owner_user_id to an arbitrary value, and immediately send commands or DMs that are supposed to be limited to that owner. The user identifier must come from authenticated claims/headers (or after validating owner visibility), not from an untrusted request field.

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