agent-conversation compound target

Trap: declaring agent-conversation view’s tuple positional required and testing only viewCommand.loader() looks correct because the conversation ID is mandatory, but direct function tests bypass Stricli’s parse-time rejection. Fix: mark the synthetic tuple optional and add a parser-level regression through Stricli proving omission reaches func() and emits ContextError. Accept only a slashless ID or exactly one nonempty <org>/<conversation-id>; malformed supplied targets use fielded ValidationError("conversation-id") before resolution or API access.