feat: toggle diff explorer and show file change indicators

docs/architecture.md

@@ -10,7 +10,8 @@ One crate; no workspace or terminal-coordinate types in the editing backend:
 
 - `editor`: owns buffer lifecycle and per-buffer text, saved state, primary/selection set, modes, search, and undo/redo; session-wide clipboard policy, independent registers and owned-system fragment metadata, semantic native repeat, action metadata, command-palette and file-picker focus/dispatch, key notation, leader/count prefixes and binding resolution, modal paste policy, saving, command ownership, capabilities, and validated edit effects. Its low-level interface returns an `Invocation` when an external command is selected.
 - `files`: owns the gitignore-aware directory/file catalog, authoritative OS paths, compact tree projection, query filtering, browse/search focus, expansion/selection restoration, navigation, and scan/error state shared by floating and docked presentations.
-- `diff`: owns searchable Before/After selection, category and focus state, request freshness, read-only comparison DTOs, and aligned rows/shared vertical and independent horizontal offsets. Changed paths form a virtual `files::FilePicker` catalog, reusing the normal tree projection, filtering, and navigation without scanning disk. It has no subprocess or terminal dependencies.
+  Virtual file leaves retain their original catalog input index for caller-owned annotations; scanned entries and directories remain unannotated.
+- `diff`: owns searchable Before/After selection, category, focus and explorer visibility, request freshness, read-only comparison DTOs, and aligned rows/shared vertical and independent horizontal offsets. Changed paths form a virtual `files::FilePicker` catalog, reusing the normal tree projection, filtering, and navigation without scanning disk. It has no subprocess or terminal dependencies.
 - `repository`: discovers jj/Git repositories and local/advertised remote revisions, builds disk snapshots and changed-file hunks, and owns isolated temporary comparison repositories with bounded, cancellable subprocesses. It never saves editor buffers or modifies active refs/checkouts.
 - `clipboard`: owns native plain-text provider selection and bounded subprocess I/O; it never computes selections or editing offsets.
 - `syntax`: owns Tree-sitter grammar detection, per-buffer incremental trees, bundled highlight/local/injection queries, and syntax byte spans; it has no terminal color/geometry or editing dependency.

docs/configuration.md

@@ -137,6 +137,8 @@ config.bind "ctrl+h", nil, mode: config.modes.tree
 
 The diff's right-docked changed-file explorer uses these same tree and selection contexts, including remaps and disabled keys. Enter opens the selected file's diff rather than an editable buffer; its catalog comes from the comparison, not a disk scan.
 
+In the diff view, Ctrl+e is reserved for hiding/showing the changed-file explorer and takes precedence over tree/selection remaps. Its query, selection, and expansion state survive hiding; the panes use the reclaimed width.
+
 Ctrl+h is **not** a Backspace alias or default deletion key in any mode. Raw Ctrl+h (0x08) and Backspace (DEL/0x7f) are distinct, as are CSI-u events. In the tree it navigates in NORMAL and INSERT without deleting query text; it never deletes file-buffer Insert text by default. Explicit `config.core.backspace` bindings remain available if desired.
 
 Ctrl+j is distinct from Enter: in the TUI's raw mode, LF is Ctrl+j and CR is Enter; CSI-u control events also work. No enhanced-terminal negotiation is required. Ctrl+m remains an Enter alias. Outside completion and selection lists, Ctrl+k still clones above in Normal/Visual, and Ctrl+j defaults to newline in Insert or submit in Command/Search. While completion is open, Ctrl+j/k cycles candidates; Enter always closes completion and inserts a newline. Enter and Ctrl+j can be rebound independently outside the completion cycle.

docs/development.md

@@ -48,6 +48,7 @@ Clipboard checks use isolated providers rather than reading or overwriting the d
 Diff checks cover staged category/filter navigation, stale request cancellation, row alignment, read-only buffer isolation, and rendered panes. Repository integration fixtures exercise Git and Git-backed jj, advertised but unfetched remote branches/bookmarks/tags, imported historical commit/change IDs, conflicts, unusual paths, binary/mode/link/submodule changes, and unchanged active metadata. Remote fixtures are local bare copies; they never push. Git fixture identities and commit dates are fixed.
 
 Changed-file explorer checks cover reuse of the compact directory tree, removed/historical paths, file-to-directory transitions, remapped tree/selection bindings, filter/open/focus transitions, right-dock geometry, and wheel routing without edits to the underlying document.
+Visibility checks preserve browsing and pane state across Ctrl+e, exclude hidden explorers from focus/wheel routing, and verify full-width review. Status checks preserve catalog associations through sorting, compaction, duplicate inputs, and file/directory collisions, and cover colored A/M/D/R markers, selected/unfocused rows, Tree/List filtering, and sanitized rename paths.
 
 ## Performance and process limits
 

docs/editing.md

@@ -211,6 +211,10 @@ Remote references such as `some-bookmark@origin` appear from remote advertisemen
 
 The read-only comparison has Before on the left, After on the right, and the changed-file explorer **docked on the right**. The explorer reuses the normal compact directory tree, filtering, and configurable `tree`/`selection` navigation. Its catalog contains only changed paths, including removed and historical files; it does not scan the working directory. Use h/j/k/l or control/arrow navigation, Enter to toggle a folder or open a file, `i` to filter, Ctrl+u to clear, and Ctrl+t to switch Tree/List. Opening a file focuses Before.
 
+**Ctrl+e** hides/shows the explorer in the diff view. Hiding reclaims its entire width for the split panes without losing the filter, selected row, folder expansion, displayed file, or pane scroll offsets. Hiding from Files moves focus to Before; showing restores Files focus. While hidden, Tab/Shift+Tab cycles only between Before and After. Ctrl+e is a reserved diff-view control and takes precedence over tree/selection remaps.
+
+File rows show colored **A** (added, green), **M** (modified, yellow), **D** (removed, red), or **R** (renamed, cyan) markers in Tree and List views, including filtered results. Rename rows show the new name followed by `← old/path`; directories have no file-status marker. Ordinary file exploration remains unannotated.
+
 Added/deleted rows are aligned with blank counterparts. Tab/Shift+Tab cycles focus between Files, Before, and After. In text panes, Up/Down or Ctrl+j/k scrolls both panes together; Left/Right or Ctrl+h/l scrolls the focused pane horizontally. Home/End goes to the first/last tree row or aligned text row. Wheel input over a text pane scrolls both panes; over Files it navigates visible tree rows without opening them. Esc first leaves filtering when the tree is focused; otherwise it closes the diff and preserves the editor's buffers, cursors, unsaved text, and undo history. Typing and pasted text cannot edit either snapshot.
 
 Binary data, missing final newlines, permission/type changes, symlink targets, and submodule pointers have explicit notices. Symlinks are not followed and submodule contents are not traversed. jj conflicts use jj's file-content projection and carry conflict notices; ordinary files remain readable. Identical-content moves are shown as renames; modified moves appear as an added and removed file.