feat(editor): edit hierarchical map nodes

docs/user/editor.md

@@ -6,7 +6,7 @@ The map editor is available at `/editor`. It is a browser-based tool for editing
 
 Use the editor when you need to:
 
-- move, rotate, or scale objects from `public/map.json`
+- move, rotate, scale, add, or delete objects from `public/map.json`
 - inspect the raw JSON generated by the editor
 - preview and edit cinematics from `public/cinematics.json`
 - create, preview, and validate dialogue entries from `public/sounds/dialogue/dialogues.json`
@@ -14,13 +14,13 @@ Use the editor when you need to:
 
 The map editor reads the same map data as the runtime scene:
 
-- `public/map.json` contains the object list.
+- `public/map.json` contains the current hierarchical runtime map.
 - `public/models/{name}/model.glb` contains the matching 3D model for each object name. `model.gltf` is still supported as a fallback during migration.
 - Missing models are displayed as gray fallback cubes, so incomplete maps remain editable.
 
 ## Map Node Format
 
-Each entry in `public/map.json` represents one object:
+`public/map.json` is hierarchical. Group nodes such as `Scene`, `blocking`, `vegetation`, or `agriculture` organize the map. Editable object nodes still use the same transform fields:
 
 | Field      | Description                                       |
 | ---------- | ------------------------------------------------- |
@@ -47,9 +47,22 @@ Only the `Editor` group is open by default. Open the other groups when you need
 2. Click an object in the scene to select it.
 3. Choose a transform mode: translate, rotate, or scale.
 4. Drag the transform gizmo in the 3D view.
-5. Check the JSON inspector if you need exact values.
-6. Use undo or redo if the transform is not correct.
-7. Export the JSON or save it to the dev server.
+5. Keep `Snap terrain on move` enabled when placing objects on the terrain.
+6. Adjust scale numerically from the `Selection` section if the gizmo is not precise enough.
+7. Check the JSON inspector if you need exact values.
+8. Use undo or redo if the transform is not correct.
+9. Export the JSON or save it to the dev server.
+
+## Adding And Deleting Nodes
+
+Use `Add Node` to create a new editable object under the `blocking` group.
+
+- The new object starts as a fallback cube at `[0, 0, 0]`.
+- Name it with the model folder name you want, for example `maison1`.
+- If `public/models/{name}/model.glb` or `model.gltf` exists, saving and reloading will display the matching model.
+- If no matching model exists, the node stays editable as a gray cube.
+
+Use the trash button in `Selection` to delete the selected node from the map tree.
 
 ## Controls
 
@@ -76,6 +89,14 @@ The `Selection` section shows the selected object name and its index in `public/
 - Click empty space or press `Esc` to clear the selection.
 - Use the `X` button to clear the selection explicitly.
 - Use the `Lock` button to protect the current selection while editing.
+- Use the scale fields to edit X/Y/Z scale precisely.
+- Use the trash button to remove the selected object.
+
+## Terrain Snapping
+
+`Snap terrain on move` is enabled by default. When you move an object and release the transform gizmo, the editor samples the terrain height at the object's X/Z position and updates its Y position.
+
+This is intended for map objects that should sit on the ground. Disable it when you intentionally need a floating object.
 
 When selection is locked:
 
@@ -90,7 +111,7 @@ The `Lock view` action switches the editor into a movement mode closer to the ru
 
 ## JSON Inspector
 
-The `JSON` section shows the raw map data that will be exported or saved:
+The `JSON` section shows the editable node data:
 
 - When no object is selected, it shows the full map node list.
 - When an object is selected, it highlights the JSON lines for that object.
@@ -101,11 +122,11 @@ Use it to verify exact numeric transform values before saving or exporting. The
 
 ### Export JSON
 
-`Export JSON` downloads the current map node list as `map.json`. Use this when you want to manually replace `public/map.json`.
+`Export JSON` downloads the current hierarchical map tree as `map.json`. Use this when you want to manually replace `public/map.json`.
 
 ### Save To Server
 
-`Save to server` is available only during local development. It writes the edited map back to `public/map.json` through the Vite dev-server endpoint.
+`Save to server` is available only during local development. It writes the edited hierarchical map back to `public/map.json` through the Vite dev-server endpoint.
 
 The button is hidden in production builds because production persistence is not implemented.