Breathalyzer 2.0 wishlist

We now have enough examples of test suites written with Breathalyzer to know what the usual pain points are. Here's a list of things that I'd like to see in Breathalyzer 2.0:

- fewer intermediate modules, and more functions available at top-level
- more functions to access and check big maps (among other things, ledgers)
- functionals to check the storage (e.g., `check_storage contract (fun storage ... )`)

Start by reviewing the existing Breathalyzer test suites and the current module and function APIs to understand the listed pain points. Clarify the desired scope and acceptance criteria for top-level functions, big-map checks, and storage-checking functionals before making changes. Done should mean the agreed wishlist items are implemented and covered by representative test suites.

Written by the indexing model from the issue text.