[FEATURE]: Enable sending messageID to shell commands #20656

Feature hasn't been suggested before.

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Describe the enhancement you want to request

PromptInput has messageID so that callers can determine the created messageID rather than opencode generating it on the spot. This is useful for bookkeeping on the client side - let's the client own the messageID and use it with other SDK methods - e.g. revert, or matching ACP updates / JRPC logs to client-owned message entities.

ShellInput on the other hand lacks this, and there the message ID is always opencode-generated. Adding this is 2 locs and will help clients do the type of matching described above also for shell messages.