Progress/timeout checks only ran when file_count advanced, so trees of
directory-only or error-dense entries (dirs, traversal errors, symlinks
never increment file_count) bypassed the entire cooperative time budget
and held the blocking thread for unbounded time, while each error entry
logged its own warn — permission-dense trees flooded the log (S13).
The stall detector was structurally unreachable: it fired on 'no file
progress between checks', but checks themselves only ran when file
progress happened, so RUSTFS_CAPACITY_STALL_TIMEOUT never did anything
since its introduction (S09).
- Progress checks (timeout + early-sampling entry) are now driven by a
visited-entry counter that also advances on directories and errors, so
every tree shape reaches the budget checks.
- Remove the unreachable stall detector and its plumbing end to end
(ProgressMonitor fields, ScanLimits, config getter, env const, stall
metric). Genuine walker wedges are handled by the hard outer
wall-clock budget from backlog#1017; no decorative protection is left.
- Cap per-entry error warns at 10 per scan with an explicit suppression
notice; had_partial_errors still records the condition.
Ref: rustfs/backlog#1016 (S09+S13 from audit rustfs/backlog#1010)
