test(aztec-nr): expand compile-failure coverage for macro panics

[vezenovm]

Motivation

PR #22733 unified the compile-failure runner and migrated four legacy cases into noir-contracts-comp-failures/, bringing total coverage to 22 contracts. That left ~28 user-reachable panic! sites in aztec-nr/aztec/src/macros/ with no dedicated test. This PR closes those gaps so every user-reachable panic has a pinned snapshot.

Approach

For each gap, a minimal contracts/<name>/ contract triggers the target panic and an expected_error file pins nargo's output verbatim. Contracts that would otherwise cascade into an unrelated panic (the generic check_each_fn_macroified message, or the "noinitcheck without initializer" message) are isolated with a #[contract_library_method] marker or a stub #[initializer] so each test pins exactly one target.

Changes

• noir-contracts-comp-failures/contracts/: 28 new contracts, one per previously-uncovered panic site (see diff for details). One contract (authorize_once_before_external) ships with an empty expected_error as a known-unreachable reproducer.
• Realistic cascading errors: In addition to the 28 isolated cases, contracts/bob_token/ pins the full cascade behavior of the current library on a realistic program. It's a token contract adapted from the https://docs.aztec.network/developers/docs/tutorials/contract_tutorials/token_contract with four broken functions.
  • Because the broken functions have realistic bodies that reference self and call each other, the snapshot captures 38 error lines (when we should only have 4 errors).
  • This gives us a baseline to measure against. After https://linear.app/aztec-labs/issue/F-578/aztec-nr-refactor-macro-validators-to-collect-errors-and-emit-a-dummy we should expect the snapshot to shrink.
• noir-contracts-comp-failures/bootstrap.sh: empty expected_error now means "expect compile success"; ACCEPT_SNAPSHOTS=1 writes an empty file when compilation succeeds. Wrong count or content falls through to the existing count-mismatch path.
• noir-contracts-comp-failures/README.md: one-line note on the empty-snapshot convention.

Follow-ups

• F-579: the #[authorize_once] attribute-ordering panic at helpers.nr:55 does not fire for the documented trigger; the reproducer ships with an empty snapshot.
• F-580: #[authorization] is pub but has no downstream consumers; its generated code references crate::authwit::* paths that don't resolve from a downstream crate, producing a 5-line cascade before the target diagnostic.

Building off of #22733