Split the 4242-line resume.rs (46% inline tests) into a canonical
foo.rs + foo/ module tree with zero behavior change:
- resume.rs (~1020): state file constants, PersistThrottle, ResumeState,
ResumeManager core (constructors, load/discovery, progress mutators,
ordinary persistence) plus root re-exports
- resume/replacement.rs (~690): replacement-intent/proof types and the
ResumeManager replacement-lifecycle methods
- resume/checkpoint.rs (~350): ResumeCheckpoint + CheckpointManager
- resume/utils.rs (~310): ResumeUtils statics
- resume/tests.rs (~1980): the inline test module as a child module
All module paths are unchanged (heal::resume::CheckpointManager and
friends resolve through root re-exports), so no consumer inside or
outside the crate changes. Items defined in child modules keep
module-private visibility; only the ten cross-module helpers gain
pub(super), which is not part of the crate API. Code is moved verbatim
apart from those visibility markers, four super::storage_api path
fixes, and the new per-module import headers.
Co-authored-by: heihutu <[email protected]>
