Snap is a magnet button in the docs (#194)

The pages described snapping as a checkbox and, in vector art, as a
Grid button. Both are now the same magnet toggle.

- Behaviors, State machines, Particles, Shaders and Vector Art name
  the magnet instead of the checkbox or the Grid button.
- Architecture lists SnapToggle and headerIcons.
- Development carries the check total 1188.

Tests:
- 1188 is computed (1184 + 4), the full run is left to CI

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Architecture.md

@@ -153,15 +153,17 @@ src/editor/panels/     AssetPanel, assetGroups (groups by type and their order,
                        plus the List, Game and Plugins tabs' own three, which stand for no asset),
                        assetMenu (the two groups of the + menu), HierarchyPanel,
                        Toolbar + toolbarIcons (five icon buttons, no captions: menu, undo, redo, play, pause, #183),
+                       headerIcons (the pictures of the tab headers' switches: the magnet, #194),
                        TilemapPanel (tools, tiles and layers of the one selected tilemap, beside the scene view, #142;
                        painting itself is SceneViewport)
 src/editor/graph/      GraphEditor (header, breadcrumb), GraphCanvas, graphView (zoom limits, grid, panAndZoom — shared with NodeBoard and the Tile tab's TileCanvas), EdgeLayer (curves and fold marks), graphMenus,
                        NodeView, NodePalette + paletteEntries (which also ranks a search), folding (hidden links, collapsed nodes), Breadcrumb + trail (the path into nested behaviors), beads (the run's pulses),
-                       AnnotationView + annotationDrag (groups and comments: what a drag carries, each thing moved once)
+                       AnnotationView + annotationDrag (groups and comments: what a drag carries, each thing moved once),
+                       SnapToggle (the magnet every tab that snaps carries, the vector art tab included, #194)
 src/editor/container/  ContainerEditor (header), ContainerCanvas (a SceneViewport on a template)
 src/editor/texture/    TextureEditor (header), TextureCanvas (picture + frames), SliceDialog (a FormDialog), sheetView (the grid maths),
                        ImagePicker + imageGrid (the "+ → Texture" dialog), checker (the transparency board)
-src/editor/vectorart/  VectorArtEditor (header: the two tools and the grid switch), VectorArtCanvas (the drawing
+src/editor/vectorart/  VectorArtEditor (header: the two tools and the magnet), VectorArtCanvas (the drawing
                        painted from core/model/vectorPath onto its own Graphics, with points and handles over it;
                        the pen puts points down, the arrow drags points, handles and whole shapes, #129),
                        ShapeList (the shapes as rows with a preview each, in the inspector; a row may be dragged to

Behaviors.md

@@ -293,7 +293,7 @@ shown on the node and editable in the inspector.
   - **A group is grabbed by its title bar only.** Its body stays transparent to the pointer, or a
     rubber band could never be drawn across the nodes it holds. The corner at the bottom right
     resizes it, and resizing moves nothing: what the box ends up around is what it carries next
-    time. With **Snap** on, the corner being dragged lands on the grid — the far one, since the near
+    time. With the magnet on, the corner being dragged lands on the grid — the far one, since the near
     corner is exactly what a resize must leave alone. A comment, framing nothing, is grabbed anywhere
     on it.
   - **Deleting one takes the box and nothing else.** The nodes stay exactly where they were — a box
@@ -310,7 +310,7 @@ shown on the node and editable in the inspector.
   the box drawn around them, and a graph holding nothing but a comment would frame the empty
   origin; `editor/framing.ts`), and the size of the graph as "N nodes · M links". It stops zooming
   out at 0.25, so a box parked far enough away can still lie outside what a fit can show.
-- **Snap** (header checkbox, off by default): a drag drops each node it carries on the nearest
+- **Snap** (the magnet in the header, an icon toggle that stays lit while on; off by default): a drag drops each node it carries on the nearest
   24 px grid line — the same grid the background draws. It takes effect on the next drag only, so
   switching it on never shuffles a graph that is already laid out, and a node nobody drags never
   moves. Every node of a selection snaps **for itself**, so dragging a group is how you line one

Development.md

@@ -13,7 +13,7 @@ npm run check        # typecheck + lint + format:check + tests, the gate CI runs
 npm run build        # writes dist/ and regenerates index.html
 ./build.sh           # the same under `set -o pipefail`, for callers that pipe the output
 php tools/make-user.php <name> <password>                     # an account; every tool signs in (see Accounts)
-node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1184 editor checks, screenshots in /tmp/gm-e2e-*.png
+node tools/seed-e2e.mjs && node tools/e2e.mjs                 # 1188 editor checks, screenshots in /tmp/gm-e2e-*.png
 GM_STEPS=20 node tools/e2e.mjs                                # or 1-12, or 6,20 — a subset while working on one step
 ./e2e.sh start [GM_STEPS]                                     # the same run detached, see below
 ./e2e.sh status                                               # live progress, or the last run's result

Particles.md

@@ -19,7 +19,7 @@ the model was chosen:
 `+` in the **Assets** panel makes a particle asset and opens the **Particles** tab on it (a
 double-click on an existing one does the same; a click only selects). The left part is the same
 canvas the Behavior and Shader tabs have: right-click places a node, drag moves, drag from a port
-links, `Snap` snaps to the 24 px grid, `Fit` frames the graph, undo takes every step back. The
+links, the magnet snaps to the 24 px grid, `Fit` frames the graph, undo takes every step back. The
 readout on the right says `N parameters` while the graph compiles, otherwise why it does not
 (`No Output node`, a bad parameter name, `Feeds itself`). A node that keeps the graph from
 compiling shows the reason on its body and a red frame; a source whose graph does not compile emits

Shaders.md

@@ -9,7 +9,7 @@ shaders; the node set is sized for the recipes below: "Adjust colors", and the c
 `+` in the **Assets** panel makes a shader and opens the **Shader** tab on it (a double-click on
 an existing one does the same; a click only selects). The tab has the
 same canvas the Behavior tab has: right-click places a node, drag moves, drag from a port links,
-`Snap` snaps to the 24 px grid, `Fit` frames the graph, undo takes every step back. The readout on
+the magnet snaps to the 24 px grid, `Fit` frames the graph, undo takes every step back. The readout on
 the right says `N properties` while the graph compiles, otherwise why it does not (`No Output node`,
 a bad property name, ...). A node that keeps the graph from compiling shows the reason on its body
 and a red frame.

State-machines.md

@@ -1,7 +1,7 @@
 A **state machine asset** is a named set of states and the moves allowed between them: its graph
 holds one `State` node per state (a title and a *Name* setting) and one edge per transition. The
 states are edited in the **State machine** tab, which is the graph
-canvas the Behavior tab uses — so placing, dragging, the header's **Snap** checkbox, renaming in
+canvas the Behavior tab uses — so placing, dragging, the header's magnet (**Snap**), renaming in
 the inspector, connecting, `Delete` and undo are the graph's.
 Double-clicking the asset (or creating it) opens the tab, like every asset with a tab; a click
 only selects. Right-click on its canvas offers a `State` and

Vector-Art.md

@@ -44,7 +44,7 @@ swing the other, which is what lets a curve break at a point.
 
 ## The tab
 
-The toolbar holds **Select**, **Pen**, **Grid** and **Fit**; the view pans and zooms like the
+The toolbar holds **Select**, **Pen**, the magnet and **Fit**; the view pans and zooms like the
 Texture tab, and the checkerboard behind the canvas is what is transparent.
 
 **Pen** draws a new shape:
@@ -63,7 +63,8 @@ Texture tab, and the checkerboard behind the canvas is what is transparent.
 - **Alt** on a point makes it round, and a round one square again.
 - **Delete** removes the selected shape.
 
-**Grid** snaps to 8 units while it is on; it is off by default. **Fit** brings the whole canvas back
+The **magnet** snaps to 8 units while it is lit; it is off by default. It is the same switch the
+graph tabs carry. **Fit** brings the whole canvas back
 into view.
 
 One gesture is **one undo step** — dragging a point across the canvas is a single entry in the undo