feat: resolve conflicts through focused two-way drafts

Replace the marker-filled three-pane resolver with a marker-free native
Draft versus frozen Alternative projected from current working text.
Preserve preexisting outside edits, native undo, dirty-save guards, all
sides/bases, and draft caret/viewports across separate History views.
Reuse DiffState alignment/highlighting/excerpts for Resolution and merge
its base-aligned rows for readonly three-way History. Hide explorer and
source-selector chrome by default.

Verified 926 tests plus actual terminal projection, History highlighting,
hunk choice, optional explorer, and guarded jj-confirmed save workflows.
Clippy completes with pre-existing warnings only. Smoke fixtures stay
unresolved in this ancestry; remove that ancestry before publication.

Size exception: approximately 1650 implementation added/deleted lines,
excluding tests/docs, kept coherent because native draft lifecycle and
aligned rendering must change together without parallel legacy modes.

src/main.rs

@@ -84,10 +84,11 @@ Diff: :diff (Normal); choose Before then After; Working checkout After edits liv
 Pull requests: :pull_requests [REMOTE]; GitHub/GitLab/Gitea Open/Closed/All tabs, type to search
       Enter opens the immutable PR head against its merge base; API auth uses provider tokens or gh/glab
 Resolve jj conflicts: :resolve opens the current working-copy conflicts in a dedicated workspace
-      Native readonly inputs above editable Result; Tab focus, :resolve.source N / :resolve.base N
-      :resolve.next/previous navigates regions; :resolve.use_source [N] chooses one region
-      :w saves and checks jj status; :resolve.next_file/previous_file switches files
-      :resolve.files focuses the list; :resolve.result focuses Result; :resolve.close closes cleanly
+      Editable marker-free Draft vs readonly Alternative; :resolve.history shows inputs/base
+      :resolve.next/previous navigates differing hunks; :resolve.use_source [N] takes a hunk
+      :resolve.source N selects Alternative; :resolve.base N selects History base
+      :resolve.draft returns to Draft; :resolve.view.toggle switches Resolution/History
+      :w saves and checks jj; :resolve.files toggles the explorer; :resolve.close closes cleanly
 
 Ruby config: $XDG_CONFIG_HOME/vamp/config.rb or ~/.config/vamp/config.rb
 Set VAMP_RUBY to choose the Ruby executable.