feat(AggLayer): B2AGG note consumption check

[mmagician]

As per the discussion here, the network target account ID is placed into NoteAttachment instead.

While at it, I created a helper function, similarly to the one we have for CLAIM notes: create_b2agg_note, and refactored the tests to use that utility.

TODO:

• apply the same check to UPDATE_GER note (once feat(AggLayer): UPDATE_GER note #2333 lands)
• what NoteAttachmentScheme should be used?

closes #2173
closes #2189

[PhilippGackstatter]

I think we need ~3 helpers in miden::standards::network_account_target, something like:

• const ATTACHMENT_SCHEME = NetworkAccountTarget::ATTACHMENT_SCHEME
• get_id(NoteAttachment) -> AccountId
  • This asserts attachment_scheme == NetworkAccountTarget::ATTACHMENT_SCHEME.
  • This assumes the attachment scheme was checked and simply returns the account ID. We may want to validate the account ID before returning?
  • A getter for note execution hint may not be necessary.
• new(AccountID, NoteExecutionMode) -> NoteAttachment
  • Looks like that's not necessary for this PR, but you're creating network notes in the bridge_out.masm using the note tag, which should be replaced with a call to this function.

Then you can just use network_account_target::get_id here. The constant is useful to add in case some other code wants to inspect the attachment scheme and branch on it instead of panicking (which is what get_id would do). I think this will be needed in other places so there is a benefit of moving this to miden::standards, and avoids low-level code here.

[mmagician]

Thanks, that's a good suggestion.

I created an issue to track this (PR already in draft), and for now added TODOs in the MASM code until that lands.