Split library.rs into library/ by area of behaviour
library.rs was 7,729 lines wiring together everything "open a remote library" touches: scanning, pulling other devices' judgements out of sidecars found along the way, writing local edits back out to the sidecar outbox, pushing/reloading XMP by hand, fetching and prefetching thumbnails and originals, generating thumbnails locally, the metadata and thumbnail background sweeps, on-disk paths for the catalog and model files, and reading the grid's cells, spans and rating filter. Same motivation as the develop.rs split (docs/dev/code-health.md CH-1): a pure, no-behaviour-change move into one file per area, each under about 1,500 lines. Tracing actual call sites rather than trusting the file's physical layout mattered here: `persist`, `load_folder_etags`, `pull_sidecars`, `load_sidecar_etags`, `record_sidecar_read` and `apply_judgement` sit textually beside the XMP push/reload functions but are called only from `run_scan` (pulling a device's own past judgements out of the sidecars a scan just walked), so they went to scan.rs and not xmp.rs. `cells` came out at over 1,800 lines once its tests moved with it and split further into cells.rs (windowed reads, trash, ordinals) and spans.rs (collection scope, manual reordering, the capture-time histogram) -- ten submodules rather than the nine first planned. Previously-private items reached from a sibling module became `pub(super)`, narrower than the whole-crate reachability one file gave them. Tests moved with the code they test; the two test fixtures used across more than one file (`scanned`, and develop.rs's `session_with_a_left_half_subject` in the matching commit) joined the shared `test_support` module alongside the existing `entry`/ `with_images`/`image_ids` helpers. `mod.rs` re-exports every module's public items under `library::`, including the `pub(crate)` `test_support` module `repairs.rs` reads its fixtures from, so no file outside `library` needed a change. The previous commit split develop.rs the same way; taken alone it left dr-ui without library.rs, so that intermediate commit does not build on its own. This one restores it.
This commit is contained in:
