Document scene rename and start-scene selection

content/editor.md

@@ -8,7 +8,7 @@ Prerequisites: a working desktop graphics session and a writable project locatio
 
 1. In Project Manager, choose **New project**, enter a name and location, choose a template, then **Create project**. For an existing project, choose **Import…**, select its location, and **Import project**.
 2. Choose **Open project**. The editor shows the project name in the toolbar. A locked project may open read-only; the **READ ONLY** indicator means authoring changes cannot be saved.
-3. Use the **Project** panel's **Scene** tab for objects and **Explorer** tab for files. Select an object to show its properties in **Inspector**. The settings gear at the top right of Project opens **Change scene**, which loads another scene with its objects and environment.
+3. Use the **Project** panel's **Scene** tab for objects and **Explorer** tab for files. Select an object to show its properties in **Inspector**. The settings gear at the top right of Project opens **Change scene**, which loads another scene with its objects and environment. Right-click a scene in that list for **Rename** and **Set as start scene**; the start choice is saved for the next project opening.
 4. Save with **File → Save scene**. Check Console for `Scene saved transactionally` or a save error. Game Settings exposes autosave; when enabled, changed scenes are saved automatically, with a periodic save check at 30 seconds.
 
 Expected result: your project opens with its scene, and a successful save persists authored changes. Save explicitly before closing or copying a project.

content/editor/scene-hierarchy.md

@@ -9,7 +9,16 @@ Prerequisites: open a writable project, stop Play, and switch the **Project** pa
 3. The editor saves pending changes to the scene you are leaving, even when autosave is off. It then replaces the hierarchy and viewport with the selected scene's objects, cameras, lights, script attachments and environment. Selection and undo history start fresh. Check Console for `Loaded scene`.
 4. Edit **Scene sky & atmosphere** in Inspector and save. Switch back and forth to verify that each scene retains its own sky, ambient light, sun and haze settings. Play, Play Solo and Run use the scene currently selected in the editor.
 
-Stop play and resolve **Review runtime changes** before switching; **Change scene** is disabled until then. Read-only projects can switch scenes for inspection, but cannot save edits. If loading the target or saving local edits fails, the current scene stays open with its edits intact; inspect Console for `Could not change scene` and fix the reported path, scene data or write-permission issue. Scene files outside the configured scenes folder are not listed. Reopening the project still starts with `main.scene` (or legacy `main.rscene`); the picker does not change the project's startup scene.
+Stop play and resolve **Review runtime changes** before switching; **Change scene** is disabled until then. Read-only projects can switch scenes for inspection, but cannot save edits. If loading the target or saving local edits fails, the current scene stays open with its edits intact; inspect Console for `Could not change scene` and fix the reported path, scene data or write-permission issue. Scene files outside the configured scenes folder are not listed. Reopening the project loads its saved start scene. Projects without an explicit choice keep using `main.scene` (or legacy `main.rscene`).
+
+## Rename a scene or set the start scene
+
+1. Open **Project → settings gear → Change scene**, then right-click a scene's filename (or two-finger click on a trackpad). This opens a second menu with **Rename** and **Set as start scene**. Right-clicking does not load the scene.
+2. Choose **Rename**, enter a new filename, then click **Rename** or press **Enter**. You may omit the extension; the original `.scene` or `.rscene` extension is retained. **Cancel** or **Escape** leaves it unchanged. Names cannot contain directory separators or overwrite another scene or its recovery/metadata files. Errors stay visible in the dialog so you can correct the name.
+3. Renaming the active scene saves pending edits first and keeps its selection and undo history. Later saves use the new filename. Recovery backups and asset metadata move with the file. Renaming a different scene leaves your current edits untouched. If the renamed scene was the start scene, its saved reference follows the rename automatically, including the default main scene.
+4. Choose **Set as start scene** to save that scene as the project default. The list marks it **Start**. This choice does not switch the scene you are editing; close and reopen the project to verify that its objects and environment load first. Play, Play Solo and Run continue to use the currently edited scene.
+
+Both actions require writable access and are unavailable during play or runtime-change review. The start choice is stored in `project.engine` as `start_scene: Some("night.scene")`, relative to the configured scenes folder. If a start scene is removed outside the editor, restore it at that path or correct the field in `project.engine`; removing the optional `start_scene` field restores the main-scene default. The editor reports a missing explicit start scene instead of silently creating an empty replacement. File renames are filesystem operations and are not reverted by scene Undo.
 
 ## Create and organise objects
 

docs/ARCHITECTURE.md

@@ -498,8 +498,15 @@ engine resources. A descriptor matching the initial `engine-project` schema is:
 )
 ```
 
-Startup scene, rendering defaults, input maps, logging defaults, and other evolving
-settings are versioned resources below `config/`, referenced by asset/resource ID as
+The optional `start_scene` field in `project.engine` stores the selected start scene
+as a path relative to the configured scenes folder. The editor persists it through
+**Change scene → right-click a scene → Set as start scene** and follows it on the
+next project open. Without this field, the editor uses `main.scene`, with
+`main.rscene` as the legacy fallback. The template manifest records the initial
+project seed and does not override this choice.
+
+Rendering defaults, input maps, logging defaults, and other evolving settings are
+versioned resources below `config/`, referenced by asset/resource ID as
 their schemas land; they are not added as an unversioned catch-all table. Machine
 overrides, trust decisions, detected toolchains, and hardware scores do not belong in
 the source-controlled descriptor. They live below `.rustic/local/` or the user's engine