feat: resolve current jj working-copy conflicts

Add a dedicated native resolver workspace with all side/base inputs,
shared editable Results, region choices, retained per-file status,
responsive rendering, and explicit nontext file choices.

Guard writes with jj working-copy locking, frozen checkout identity,
exact disk baselines, native dirty-buffer protection, and asynchronous
jj snapshot/status confirmation. Historical comparisons remain readonly.

Verified all 916 tests and live isolated terminal workflows covering text
regions, narrow layouts, binary bytes and symlink targets/types.
Clippy completes with pre-existing warnings only.

Size exception: 2614 implementation additions/deletions excluding tests
and docs. Native workspace integration, explicit file choices and the
safe save/check operation are retained as one complete behavioral slice.

docs/configuration.md

@@ -223,6 +223,7 @@ Normal `C` / `D` / `Y` change/delete/copy the cursor-to-line-end suffix through
 | Normal | `follow_link` |
 | Normal | `diff`, `diff.mode.toggle`, `diff.view.toggle`, `diff.orientation.toggle`, `diff.review.toggle` |
 | Normal, Insert, Visual, Command, Search | `diff.close` |
+| Normal | `resolve`, `resolve.next`, `resolve.previous`, `resolve.use_source`, `resolve.source`, `resolve.base`, `resolve.next_file`, `resolve.previous_file`, `resolve.files`, `resolve.result`, `resolve.close` |
 | Normal, Insert, Visual, Command, Search | `word_wrap.toggle` |
 | Normal, Insert, Visual, Command, Search | `git_blame.toggle` |
 | Normal | `pane.split_horizontal`, `pane.split_vertical`, `pane.focus_left`, `pane.focus_down`, `pane.focus_up`, `pane.focus_right`, `pane.close`, `pane.force_close` |