feat: add Git and Jujutsu gutter indicators

docs/architecture.md

@@ -84,7 +84,9 @@ Already-ready mouse reports share a redraw: at most 64 reports are applied in th
 
 Ratatui's bounded layout cache is enabled: unchanged geometry and constraints reuse solved rectangles during scrolling; resizes and panel-layout changes use their own cache keys.
 
-The buffer viewport includes a fixed left gutter with right-aligned hybrid line numbers: the highlighted primary cursor line shows its one-based absolute number; every other line shows its distance from the primary. Secondary carets do not establish separate numbering origins. Gutter width follows the total line count plus one separator cell, including an empty final row after a trailing newline. Horizontal scrolling affects only text; search/selection highlights and carets never paint over the gutter. Rows beyond the buffer have no number. The gutter is hidden when it would leave no text column.
+The buffer viewport includes a fixed left gutter with right-aligned hybrid line numbers: the highlighted primary cursor line shows its one-based absolute number; every other line shows its distance from the primary. Secondary carets do not establish separate numbering origins. Width follows the total line count plus one separator cell, including an empty final row after a trailing newline; `git_gutter` bar/symbol modes add one marker cell between the number and separator. Number-color/none modes add no width. Horizontal scrolling affects only text; search/selection highlights and carets never paint over the gutter. Wrapped continuations and rows beyond the buffer have no number or marker. The gutter is hidden when it would leave no text column.
+
+Repository gutter work runs off the render/editor thread. Revision/path-validated marker vectors belong to ordinary source buffers, not historical snapshots; panes and tabs borrow their own buffer's markers. The worker compares editor text with Git HEAD or Git-backed jj's single parent, independently of save baselines and index state. The frontend paints green additions, red deletion anchors, and yellow modifications as `▌`, symbols, or number colors; current-line cyan/bold overrides repository colors in number-color mode.
 
 ## Syntax caches
 

docs/configuration.md

@@ -14,6 +14,7 @@ Vamp.configure do |config|
   config.leader = "space"
   config.clipboard_mode = "system"
   config.git_blame = true # false disables current-line attribution
+  config.git_gutter = "bar" # or "symbols", "line_numbers", "none"
   config.file_explorer_side = "right"
   config.file_explorer_view = "tree"
   config.file_picker_view = "tree"
@@ -48,6 +49,10 @@ Plugin paths resolve relative to the config file, not the shell's working direct
 
 `config.git_blame` defaults to `true`; set it to `false` to disable current-line inline Git blame and its background worker. Only literal Ruby booleans are accepted; other values reject the configuration. Toggle it for the running session with `:git_blame.toggle`, its palette action, or a custom binding such as `config.bind "leader b", config.core.git_blame.toggle`. There is no default shortcut.
 
+`config.git_gutter` defaults to `"bar"`: a fat `▌` beside each changed line number, followed by a blank before the text. `"symbols"` uses `+` / `-` / `~` instead. Added, removed, and modified lines use green, red, and yellow respectively. `"line_numbers"` colors the existing numbers without adding a marker column; the current line retains its cyan/bold caret highlight. `"none"` disables repository indicators, not line numbers. Other modes retain diagnostic number colors independently of repository markers. Unsupported strings, empty strings, and non-string values reject the configuration.
+
+Indicators compare the current editor text (including unsaved edits) against Git `HEAD`, or the parent `@-` in Git-backed jj repositories, rather than against the last save or Git index. Line endings use the editor's LF normalization. They refresh after edits/saves, on focus regain, and once per second for repository changes. Historical snapshots do not receive live indicators. Eligible named files not yet on disk show nonempty unsaved text as added; tracked files missing on disk still compare their buffer text against the baseline. Non-repository, ignored, binary, symlink, and unsupported files have no indicators; neither do jj working changes with multiple parents. Both colocated and non-colocated Git-backed jj repositories are supported. Files above 16 MiB report an error and clear their indicators; request batches are limited to 64 MiB or 1024 files.
+
 `config.diff_context_lines = 10` sets how many unchanged aligned lines appear above and below each diff change; it defaults to `10` and accepts nonnegative integers, including `0` for changes only. `config.diff_expand_lines = 15` sets how many additional lines each directional expansion reveals per keypress; it defaults to `15` and accepts positive integers. Both are bounded by the platform's Rust `usize` maximum (`18446744073709551615` on 64-bit systems). Floats, strings, booleans, negative or oversized values, and a zero expansion step reject the whole Ruby configuration.
 
 `config.diff_view_mode` selects the initial view for each new comparison: `"split"` (default) or `"unified"`. `config.diff_split_orientation` selects `"vertical"` (left/right, default) or `"horizontal"` (above/below) for split views. Invalid values reject the configuration. Normal-mode **Space v** cycles split/unified; **Space s** flips split orientation. These controls affect the current comparison, not startup defaults, and retain their choices across file switches and tabs. Orientation changes apply only in split view.

docs/development.md

@@ -55,6 +55,8 @@ 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.
 
+Repository gutter checks cover LF/CRLF normalization, additions/replacements/deletion anchors, staged/disk/unsaved Git text, unborn and missing named files, ignored/unsupported paths, read-only colocated/non-colocated jj queries, stale results and per-buffer isolation, plus rendered modes, colors, current-line precedence, wrap/scroll and narrow/split geometry. Live PTY smoke verifies all four modes, edit/undo refresh, external Git HEAD changes, and jj parent changes without editor restart.
+
 Diff LSP integration checks reuse the real framed-protocol subprocess with test-controlled response/publication gates and local Git comparisons. Cover both immutable historical sides and writable Working After, snapshot text/URI isolation, Unicode UTF-16 requests/targets/diagnostics, normal overlong-column clamping, hover, completion/undo, and read-only editing guards. Definition routing must distinguish ranges overlapping actual changed rows from wholly unchanged/context/omitted targets, use full location-link target ranges with exact selection reveal and exclusive endpoints, route canonical aliases and old/new rename paths, load other changed files on demand, handle added/deleted files, preserve original tabs/panes/excerpts and shared dirty targets, retain snapshot identity in ordinary tabs, and fail atomically for missing/non-UTF-8 files, invalid ranges, and unsupported URIs. Delayed/superseded replies must remain stale across caret moves, edit/undo, side/file/pane/tab changes, and comparison closure/replacement; publications for disposed snapshot identities must not reach their replacements. Private editor checks gate pending repository-load cancellation and exact-row reveal without timing assumptions. Before marking the TODO complete, run native integration/unit checks and an actual terminal smoke of focused diff LSP actions, changed-line routing, external new tabs, and immutable/editable side behavior.
 
 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.

docs/editing.md

@@ -4,6 +4,10 @@
 
 Default controls and editing behavior. For custom bindings, see [configuration](configuration.md); for language-server commands, see [native LSP](configuration.md#native-lsp).
 
+Ordinary documents show repository changes beside their hybrid line numbers by default: green `▌` for additions, red for removals, and yellow for modifications. [Configure `git_gutter`](configuration.md) to use `+` / `-` / `~`, colored numbers, or no change indicators. Bar/symbol gutters keep the order **number, marker, blank, text**; number-only modes use no extra column. Horizontal scrolling never moves indicators, and wrapped continuation rows do not repeat them.
+
+The baseline is Git `HEAD` or Git-backed jj's parent `@-`, so indicators include unsaved edits and remain after saving until the repository baseline changes. A deletion marks the next surviving source row; at EOF it marks the last editor row, including the final empty row after a trailing newline. An empty file anchors removals on row 0. Replacements mark paired rows modified and extra current rows added. Historical snapshots do not show live changes. Eligible named files not yet on disk show nonempty unsaved text as added; tracked files missing on disk still compare their buffer text against the baseline. Non-repository/ignored/binary/symlink files, files over 16 MiB, and jj changes with multiple parents have no indicators.
+
 ## Default editing keys
 
 | Mode | Keys |