Live drive probing (cold-single vs in-stream batch vs centered window,
one clean uncached read per sector) showed recovery RATE is identical
across approach: 3/5 every mode. The drive's per-sector ECC is
media-bound and partly stochastic, NOT approach-bound. So scatter
(seek-away recalibration + far-anchor re-read) does not improve recovery
and is dead weight — removed (function, read_good_sectors, SCATTER_*
consts, and its tests).
Add SubRanges: the still-bad (pos,len) sub-ranges of a section with
remove()/split, the work-list foundation for the upcoming per-section
recovery decomposition (recover_section -> stream/bisect/retry phase
helpers). Unit-tested; unused until the decomposition lands.
25 patch + 8 AB profile tests green; precommit clean on Rust 1.86.
Matthew Jackson
923b9edbf4