feat(ui): offer a cube navigator alongside signed axes (#664)

Adds a View navigator preference (Navigation page) with an optional cube navigator alongside the signed axes, which stay the default (#165).

docs/control-protocol.md

@@ -64,7 +64,7 @@ unit regardless of the design, pass an expression with one: `"value": "50 mm"` o
 | `ui.sketchToScreen` | `points`: `[[x, y]…]` in active-sketch coordinates | their screen points (null when behind the camera) |
 | `ui.dialogInput` | `index` | what clicking an input's Select chip does: picks go to that input |
 | `ui.at` | `world: [x,y,z]` \| `sketch: [x,y]` \| `plane: "XY"` \| `axis: "Z"` \| `dimension: "d1"` (its value text) \| `handle: "arrow"` (a manipulator handle, see `scenario::publish_handle`) | the screen point (a scenario step's target; see `crates/ui-egui/src/scenario.rs`) |
-| `ui.handles` | `prefix?` | the handles drawn last frame, `[{name, x, y}]`: toolbar buttons and drop-down items `toolbar:<command id>` (the button alone: `button:<command id>`; a drop-down row: `dropdown:<command id>`, highlighted `dropdown_hot:<command id>`, its pin `dropdown_pin:<command id>`; Customize Toolbar's check boxes `customize:<command id>`), panel labels `panel:<tab>:<panel>`, browser rows `row:<label>` and fold arrows `fold:<label>`, manipulator handles; orientation tips `axis_view:x`, `axis_view:-x` (and y/z) |
+| `ui.handles` | `prefix?` | the handles drawn last frame, `[{name, x, y}]`: toolbar buttons and drop-down items `toolbar:<command id>` (the button alone: `button:<command id>`; a drop-down row: `dropdown:<command id>`, highlighted `dropdown_hot:<command id>`, its pin `dropdown_pin:<command id>`; Customize Toolbar's check boxes `customize:<command id>`), panel labels `panel:<tab>:<panel>`, browser rows `row:<label>` and fold arrows `fold:<label>`, manipulator handles; signed-axis tips `axis_view:z`, `axis_view:-y`; optional cube facets `navigation_cube:top`, `navigation_cube:top_front_right`, controls `navigation_cube:control:home` (and other actions), plus signed-axis aliases for visible cube faces; Preferences navigator picker `prefs:navigator`, options `prefs:navigator:Signed axes` and `prefs:navigator:Cube` |
 | `ui.editFeature` | `feature` (id or name) | what double-clicking a timeline item does: rolls back to it and opens its dialog filled in (sketches open in sketch mode) |
 | `ui.scroll` | `x`, `y`, `delta?` | wheel zoom at the cursor |
 | `ui.key` | `key` (egui key name, `Enter`, `Escape`…), `cmd?`, `shift?` | |
@@ -99,10 +99,39 @@ channel; see [mcp.md](mcp.md).
 {"id":5,"method":"ui.screenshot","params":{"path":"/tmp/part.png"}}
 ```
 
+Preferences → Navigation → View navigator offers **Signed axes** (the original default) and
+**Cube**. This choice is saved independently of the mouse preset. The control channel selects it
+with `ui.prefs {"navigator_style":"axes"}` or `ui.prefs {"navigator_style":"cube"}`.
+Existing settings without this field keep signed axes. Signed-axis tips choose principal views;
+clicking an aligned tip again reverses the view.
+
 Hold Shift during an orbit gesture to snap to the nearest standard or diagonal view. This applies to
-right-drag, the Orbit navigation tool, and dragging the axis view. Under the default preset,
-Shift+middle also orbits with snapping; middle alone pans. Axis-view tips use world coordinates,
-regardless of the up-axis preference. Clicking an aligned tip again flips to its opposite.
+right-drag, the Orbit navigation tool, and dragging either view navigator. Under the default preset,
+Shift+middle also orbits with snapping; middle alone pans. Cube faces choose principal views,
+and corners choose isometric views. The middle of each cube edge belongs to its face. Face names
+follow the up-axis preference; the small X/Y/Z triad shows world axes. Clicking the same face keeps that view.
+The inward-pointing arrows orbit by 90 degrees; the curved arrows at the upper right roll the
+view by 90 degrees. The Home button at the upper left returns to isometric and the lower-right circle
+fits the model.
+
+The cube is subdued while idle. Hovering its area brightens the cube and navigation bar and
+reveals the surrounding controls; the picked face or corner gets a pale blue fill and
+blue outline. Moving away restores the subdued state. Navigation-bar controls also brighten
+when hovered or when a navigation tool is active.
+
+The cube has six face targets and eight corner targets, with no edge targets. Corner picking
+regions lie on the six flat faces, preserving sharp corners with no permanent subdivision
+lines. Hovering a corner highlights its parts on the adjacent visible faces together.
+
+The cube widget occupies a compact 112-point square in the viewport corner. A straight-on
+cube face is approximately 55 points wide; painting and picking scale together. Face labels
+are stretched vertically. View clicks ease through intermediate orientations when Navigation
+animated view changes is enabled (the default), at the configured animation speed.
+
+The cube runs `view.navigate` through the command engine. Programmatic callers pass `camera`
+and either `direction: [x,y,z]` in the camera's up-axis frame or `action` (`left`, `right`, `up`,
+`down`, `clockwise`, `counterclockwise`, `home`, `fit`). The result contains `camera` and `fit`;
+UI callers apply the camera with their animation preference, without editing the design.
 
 Shift-orbit snapping includes 45-degree edge views and isometric corner views, with a
 lightly damped spring transition and a small boundary margin to prevent flicker.

docs/features.md

@@ -1,6 +1,6 @@
 # Features
 
-SolidCraft's commands by area, generated by `cargo xtask features` from the command registry (`solidcraft-cli commands`). **322 commands.** Every command runs the same way from the toolbar, a script, `solidcraft-cli exec <id> '<json>'`, the control channel and MCP; parameters are in the [command reference](book/src/reference/commands.md) (`cargo xtask book`). Status and plans: [ROADMAP](../ROADMAP.md).
+SolidCraft's commands by area, generated by `cargo xtask features` from the command registry (`solidcraft-cli commands`). **328 commands.** Every command runs the same way from the toolbar, a script, `solidcraft-cli exec <id> '<json>'`, the control channel and MCP; parameters are in the [command reference](book/src/reference/commands.md) (`cargo xtask book`). Status and plans: [ROADMAP](../ROADMAP.md).
 
 ## Sketch (98)
 
@@ -207,7 +207,7 @@ SolidCraft's commands by area, generated by `cargo xtask features` from the comm
 | Assign Plastic Rule | `plastic.assign_rule` | PLASTIC › SETUP |
 | List Plastic Rules | `plastic.rules` | – |
 
-## Components (12)
+## Components (16)
 
 | Command | Id | Toolbar |
 |---|---|---|
@@ -223,6 +223,10 @@ SolidCraft's commands by area, generated by `cargo xtask features` from the comm
 | Paste New | `component.paste_new` | – |
 | Capture Position | `component.capture_position` | SOLID › POSITION |
 | Revert Position | `component.revert_position` | SOLID › POSITION |
+| Insert Design | `component.insert_design` | – |
+| Update Links | `component.update_links` | – |
+| Break Link | `component.break_link` | – |
+| List Links | `component.links` | – |
 
 ## Assembly joints (11)
 
@@ -490,7 +494,7 @@ SolidCraft's commands by area, generated by `cargo xtask features` from the comm
 |---|---|---|
 | Delete | `selection.delete` | – |
 
-## `view.*` (5)
+## `view.*` (6)
 
 | Command | Id | Toolbar |
 |---|---|---|
@@ -499,3 +503,4 @@ SolidCraft's commands by area, generated by `cargo xtask features` from the comm
 | Delete Named View | `view.delete` | – |
 | List Named Views | `view.list` | – |
 | Restore Named View | `view.apply` | – |
+| Navigate View | `view.navigate` | – |