feat(standards): add the pass-through auth component

[mmagician]

Stacked on #3713 - review that first; this diff is only the auth component and what follows from it.

Closes the second half of #3709, "skipping fee note creation".

What it does

AuthPassThrough asserts the account's commitment is the one the transaction started with, never increments the nonce, and creates no TX_FEE note. That is what makes a pass-through account immutable: nothing can alter it, so transactions against it never conflict and a batch builder can append one to every batch it builds concurrently.

With NoAuth neither property held. Any third party could run a transaction against the account and change its state, breaking the concurrency guarantee independently of the script; and on a fee-charging chain the auth procedure funded a TX_FEE note out of the account's vault, which is both a state change and impossible for an account the script has just emptied.

What follows from it

• assert_vault_unchanged is removed. The auth procedure's commitment check subsumes it - it runs after the tx script and also covers storage - so the script's own call became redundant. The script's docs say plainly that the guarantee is a property of the account composition, which the script cannot verify.
• The action component is renamed PassThroughSweep (miden::standards::pass_through::sweep), since it is down to a single procedure and other pass-through actions need somewhere to land.
• Both components are registered with StandardAccountComponent and AccountComponentInterface. Without the auth variant, AccountInterface::new finds no auth component and panics - AccountInterface::from_account would have been a panic on valid input.

Worth reviewing

• The account authenticates nothing. Anyone can execute a transaction against it and choose where the assets passing through go. Assets are only safe in transit if the input note's own script constrains its destination, or if they were already unrestricted - TX_FEE notes are the latter, which is why fee forwarding is sound while routing a P2ID note through such an account would not be.
• Fee-lessness is a property of the procedure, not the transaction. The assert requires a zero net vault delta, not the absence of withdrawals, so another script could still route assets an input note deposited into a fee note of its own.
• Such an account cannot be created by a transaction - the nonce is never incremented and the kernel rejects a zero nonce - so it has to be provisioned out of band. Any asset it holds is then permanently unspendable. Pinned by pass_through_auth_cannot_create_an_account.
• Fee-less transactions need a batch builder that accepts them. Nothing in the protocol prices them; that is the node-side work in 0xMiden/node#2501.

Testing

Three tests in crates/miden-testing/tests/auth/pass_through.rs: a transaction leaving a deposit in the account is rejected, an account-creating transaction fails on the nonce, and on a chain with a non-zero verification_base_fee the only output is the P2ID note with the account unchanged. Plus an interface test pinning the component registration that would otherwise panic. The existing script tests move over to AuthPassThrough. make lint and make doc clean; miden-standards and miden-testing green.

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