Jar file effects: deterministic rewriting, and selective class extraction.

The decisions these functions act on live in hive-build.promote.naming; what
is here is only the IO.

Everything the freeze gate must read from the world: source text at HEAD and
at the previous release tag, that tag's age, and this commit's message.

Isolated here so `promote.freeze` and `promote.api-surface` stay pure and
testable without a repository.

Verify the built AOT jar in a fresh JVM containing only its declared
dependency classpath. Provided/overlay dependencies are deliberately absent.

Executes a Plan against a handler registry.

Knows nothing about tools.build. A handler is (fn [ctx step] -> result)
keyed by :step/kind, which is the seam the whole suite exercises: substitute
recording handlers and an entire release runs with no filesystem, no
network, and no jar.

The tools.build adapter: gathers the Project and Facts a plan is computed
from, and supplies the handler that executes each step kind.

This is the only namespace that knows tools.build and deps-deploy exist.