## Summary

Replace the broken rescan-warning rate limiter, which repeatedly emitted
“not logging more” without advancing its counter.

- Keep the last 10 queued path occurrences per watcher backend,
preserving full paths.
- Build and write rescan reports in the existing background dispatch
task, keeping blocking log I/O off the native watcher reader.
- Emit one error line per dispatched rescan after coalescing duplicate
pathless rescans and before registration fan-out, containing the
backend-provided reason, affected paths, and preceding paths.
- Remove the redundant rescan warnings and rate-limit bookkeeping
without changing rescan scheduling.
- Add one focused test for the path history and report contents.

## Verification

- `corgi test -p fs --lib` — 23 tests passed.
- `corgi test -p fs --features test-support --test integration` — 24
tests passed.
- `corgi fmt -p fs -- --check`
- `git diff --check`

Release Notes:

- Improved filesystem watcher rescan diagnostics and removed repetitive
“not logging more” warnings.