Add visual mode, node registers, search and the jump list (stage 8c)

The rest of vim, on nodes. Visual mode takes in what lies between where
it started and the cursor: on the canvas, every node the rectangle from
one end's box to the other's touches; in the outline and the Note view,
the nodes in between in reading order. V takes whole branches, Ctrl+click
and Ctrl+drag pick with the mouse, and the operators take exactly what's
selected: d, y, > and <, M, and the pickers on every node at once.

Registers now hold text or nodes, so yy, dd and x keep what they take and
p, P and ]p paste it, layout and links included. "+ is the system
clipboard through arboard: nodes go there as Markdown in the user's
format (## headings, a --- tag list, the body), and come back whole while
the clipboard still holds them. clipboard = "unnamedplus" makes plain
yanks use it, as in vim.

. repeats the last change made with keys, with the text typed after it.
/ opens a Telescope-style search: fuzzy matches over titles, tags and
bodies, best first, with the note of the one you're on beside them; n
and N go on with it, and :find searches straight away. Each pane keeps a
jump list for Ctrl-o and Ctrl-i that crosses documents and reopens closed
ones. Capital marks lead into any document and, like the small ones, are
kept in memory.ron. gd follows a cross-link, and :marks, :jumps and
:registers list what they hold.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/view/outline.rs

@@ -25,6 +25,8 @@
 //! Rows wider than the view (a deep tree, a long title) are cut at its right
 //! edge; `zh` and `zl` or the wheel sideways scroll them.
 
+use std::collections::BTreeSet;
+
 use ratatui::Frame;
 use ratatui::layout::{Position, Rect};
 use ratatui::style::{Color, Modifier, Style};
@@ -36,6 +38,7 @@ use crate::app::commands;
 use crate::app::mode::Mode;
 use crate::app::popup::MenuFor;
 use crate::app::text_edit::{EditAt, StartEdit, TextEdit};
+use crate::app::visual::selection;
 use crate::input::bindings::Context;
 use crate::input::command::{Command, Motion};
 use crate::input::engine::Typed;
@@ -76,6 +79,8 @@ pub struct OutlineView {
     scrolled: bool,
     /// The title being edited, as drawn.
     editing: Option<Editing>,
+    /// What's selected in visual mode.
+    picked: BTreeSet<NodeId>,
 }
 
 /// One row, ready to draw.
@@ -117,6 +122,10 @@ impl OutlineView {
         let (doc, theme, glyphs) = (ctx.doc, ctx.theme, ctx.theme.glyphs);
         let visible = Visible::new(doc, ctx.cursor, ctx.settings.focus);
         let edit = ctx.mode.title_edit();
+        self.picked = match ctx.mode {
+            Mode::Visual(visual) => selection(visual, ctx, ViewKind::Outline).into_iter().collect(),
+            _ => BTreeSet::new(),
+        };
         // The color of the lines from a node to its children, as on the
         // canvas: the node's own, or dim when it has none.
         let line_style = |id: NodeId| {
@@ -185,6 +194,8 @@ impl OutlineView {
         let muted = Style::new().fg(theme.muted);
         let title_style = if id == ctx.cursor {
             Style::new().fg(Color::Black).bg(theme.accent).add_modifier(Modifier::BOLD)
+        } else if self.picked.contains(&id) {
+            Style::new().fg(Color::Black).bg(theme.visual)
         } else if style.faded {
             muted
         } else {
@@ -418,7 +429,11 @@ impl View for OutlineView {
     }
 
     fn contexts(&self, mode: &Mode) -> &'static [Context] {
-        contexts_for(mode, &[Context::Outline, Context::Normal, Context::Motions])
+        contexts_for(
+            mode,
+            &[Context::Outline, Context::Normal, Context::Motions],
+            &[Context::Visual, Context::Outline, Context::Motions],
+        )
     }
 
     fn layout(&mut self, area: Rect, ctx: &ViewContext<'_>) {
@@ -459,8 +474,8 @@ impl View for OutlineView {
 
     fn command(&mut self, typed: &Typed, ctx: &ViewContext<'_>) -> Option<Vec<Action>> {
         match ctx.mode {
-            Mode::Move(grab) => return commands::reorder(typed, *grab, ctx),
-            Mode::Normal => {}
+            Mode::Move(grab) => return commands::reorder(typed, grab, ctx),
+            Mode::Normal | Mode::Visual(_) => {}
             Mode::Text(_) | Mode::Command(_) | Mode::Popup(_) => return None,
         }
         let rows = isize::try_from(typed.times()).unwrap_or(1);