Tidy a branch and line nodes up (stage 9a)

The first small part of stage 9 (v1.1). <Space>= then m, c or g (the
user's pick: leader menus), or :tidy map|chart|grid, lays out the
cursor's branch while its top node stays put: a mind map puts each node
in the middle of its children (the user's pick), an org chart puts them
side by side below, and a grid makes a block of cards beside the node
(the user's pick), a card's own branch going along as a mind map. Every
node of the branch gets a place, folded away or not (the user's pick),
as one undo step, and the message says when the branch now covers nodes
outside it.

The lines follow the layouts: a parent whose children are all below it
sends its branches down to a shared bend, and a new child of it goes
beside the last one; a grid card behind another isn't joined by a line,
which would look like it joins the two cards.

In visual mode, <Space>a then h, l, k, j or c lines the selection up on
the box around it, each node bringing its branch along, and : opens the
command line on the selection: :align and :tidy take it, and so do
:color, :border, :style, :tag and :fold, as one undo step. The layouts
are pure functions in view::canvas::arrange, applied as one
EditOp::Reposition. Layout and Side moved from the parser to the model
so keys can name them.

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

DESIGN.md

@@ -249,6 +249,33 @@ lines.
   document by uid (a file moved or renamed by hand), and keeps the path it
   finds.
 
+**Tidying and lining up** (settled in part 9a)
+- `<Space>=` then `m`, `c` or `g` (the user's pick: leader menus), or
+  `:tidy [map|chart|grid]`, lays out the cursor's branch: its top node
+  stays where it is, and every node under it gets a place, folded away or
+  not (the user's pick: unfolding later shows it tidy too). One undo step.
+  What's outside the branch stays put, even under it, and the message says
+  how many nodes the branch covers now.
+- A mind map puts each node in the middle of its children (the user's
+  pick), with their branches stacked to the right. An org chart puts the
+  children's branches side by side below, each node in the middle above
+  its own. A grid makes a block of cards beside the node (the user's pick),
+  filled left to right, about as many columns as rows; a card's own branch
+  goes along with it, as a mind map.
+- The lines follow: a parent whose children are all below it sends its
+  branches down to a shared bend, and a new child of it goes beside the
+  last one. In a grid, a card behind another in its row isn't joined by a
+  line: the bit showing between the two cards would look like it joins
+  them.
+- In visual mode, `<Space>a` then `h`, `l`, `k`, `j` or `c` lines the
+  selection up: left, right, top or bottom edges, or middles in a column,
+  on the box around them all. Each brings its branch along (with `V`, each
+  branch goes by its top). `<Space>=` tidies each selected branch.
+- `:` in visual mode opens the command line on the selection (the status
+  bar keeps counting it): `:align` and `:tidy` take it, and so do `:color`,
+  `:border`, `:style`, `:tag` and `:fold`, setting every selected node as
+  one undo step, the way the pickers do.
+
 **Views, panes and popups** (settled in stage 7)
 - The Note view is made of parts: the title, the tags, the body, each link
   (out, then in) and each child. `j` and `k` step through them, with a bar
@@ -478,7 +505,7 @@ text).
 | **Create and edit** | `o` `O` sibling below / above · `a` child · `i` `A` Enter edit the title · `I` edit from its start · `cc` `S` retype |
 | **Operators** | `dd` or `dab` delete branch · `dib` delete children · `x` delete just the node · `yy` `yab` `yib` yank · `p` paste as children · `P` paste as siblings below · `>>` `<<` indent / outdent · `"a`–`"z` and `"+` registers · `.` repeat · `u` `Ctrl-r` undo / redo |
 | **Modes** | `v` `V` visual · `M` move · `C` connect · `:` command · Esc back to normal |
-| **Leader** `<Space>` | `c` color · `s` style · `B` border · `t` tags · `p` new portal (`:portal `) · `i` inbox · `b` documents · `v` then `c`/`o`/`n` for canvas / outline / note · `w` which-key on/off · `?` help |
+| **Leader** `<Space>` | `c` color · `s` style · `B` border · `t` tags · `=` tidy (`m` map, `c` chart, `g` grid) · `p` new portal (`:portal `) · `i` inbox · `b` documents · `v` then `c`/`o`/`n` for canvas / outline / note · `w` which-key on/off · `?` help |
 | **Panes, documents** | `Ctrl-w v` `Ctrl-w s` split · `Ctrl-w hjkl` focus · `Ctrl-w w` the next pane · `Ctrl-w c` close · `Ctrl-w o` only · `Ctrl-w =` even sizes · `gt` `gT` `]b` `[b` next / previous document · `ZZ` close pane (the last one quits) |
 | **Outline** | `j` `k` rows · `h` `l` parent / first child · `zb` every body · `M` then `j` `k` (`J` `K`: 5) swap with siblings, `h` out, `l` under the one above |
 | **Note view** | `j` `k` parts · Enter `i` `A` edit the part (`I` from its start, `cc` `S` anew), or go to that link or child · `h` `l` the sibling before / after |
@@ -488,7 +515,7 @@ text).
 | **Inside text** | `h j k l w b e 0 ^ $ gg G` (and arrows, Home, End) · `f t F T ; ,` · `d` `c` `y` with any motion and `iw aw i" a" i( a(` · `x X s S D C Y` · `r ~ J p P` · `u Ctrl-r .` · `i a I A` back to typing · `o O` (title: a new sibling; body: a new line) · Esc done |
 | **Move mode** | `hjkl` 1 cell · `HJKL` 5 cells · `M` branch ↔ node · Enter or Esc done |
 | **Connect mode** | move to the target as usual (or click it) · Enter link · `d` remove (a branch: cut) · `>` attach as child · `<Space>` style menu (`s` named, `a` arrows, `l` line, `c` color, `t` label) · Esc cancel (takes it all back) |
-| **Visual** | `d` `x` `y` `>` `<` `M` and `<Space>c` `<Space>s` `<Space>B` `<Space>t` act on the whole selection · `o` swaps ends · `v` `V` switch, or stop · Ctrl+click, Ctrl+drag pick with the mouse |
+| **Visual** | `d` `x` `y` `>` `<` `M` and `<Space>c` `<Space>s` `<Space>B` `<Space>t` act on the whole selection · `<Space>a` then `h` `l` `k` `j` `c` line it up · `<Space>=` tidies each branch · `:` a command on the selection · `o` swaps ends · `v` `V` switch, or stop · Ctrl+click, Ctrl+drag pick with the mouse |
 
 ## Files
 
@@ -662,7 +689,7 @@ cumulus/
    │               keymap (+ keys.toml), engine (counts, registers, operators), mouse
    ├─ command/     registry, parse, complete, history
    ├─ view/        mod.rs (the View trait), canvas/ (camera, boxes, lines, route, scene, render,
-   │               navigate, placement, view), outline, note; later board
+   │               navigate, placement, arrange (:tidy, :align), view), outline, note; later board
    ├─ ui/          text_input (a line of text and its cursor), text_editor/ (vim inside text:
    │               motion, object, layout), list (the popup list help, menus and pickers
    │               share), card (the K card), status_bar, document_bar, which_key,
@@ -687,8 +714,8 @@ cumulus/
 ```
 
 The end-to-end tests are in `app/tests.rs` (with `app/tests/files.rs`,
-`app/tests/config.rs`, `app/tests/vim.rs`, `app/tests/connect.rs` and
-`app/tests/portals.rs`): they copy the sample
+`app/tests/config.rs`, `app/tests/vim.rs`, `app/tests/connect.rs`,
+`app/tests/portals.rs` and `app/tests/arrange.rs`): they copy the sample
 documents to a temporary folder, type keys and click on a test terminal, and
 check the screen, the documents and the files.
 
@@ -770,7 +797,9 @@ it.
 Each stage ends with `cargo build`, `cargo lint` and `cargo test` passing, and
 one commit. Stage 8, as big as stages 5 to 7 together, comes in four parts
 with a commit each, and a pause after each for the user to try it (their
-choice).
+choice). Stage 9 comes in small parts the same way (their choice too): 9a
+`:tidy` and align, 9b branch out, 9c export and import, 9d the search
+across documents, 9e the Board.
 
 ## Crates and tooling