The library holds only the state its own types need when a Ctrl+C
arrives: the interrupted flag flows check to stand down, the cleanup
hook registry for resources that must not outlive the process (the
ephemeral build chroot), and the live view's reporter slot. The
signal handling itself is CLI wiring and lands separately: nothing
here installs handlers, prints or exits, so a library consumer
embedding these types keeps its own signal disposition.
Codify what the history already does so agents and new contributors do
not have to reverse-engineer it: the fmt/clippy gates mirroring CI's
-Dwarnings, the <scope>: <summary> commit format with the per-module
scope table, and the library-side invariants (missing_docs, report
ports, data/*.yml embeds, README parity for user-facing changes).