d08bee1361
Stage-10 editor-UX follow-up, second half of in-editor script authoring: - "✏ Edit" button on the Script inspector section (enabled once a source is assigned) and double-click on any script in the Project panel open the .rhai in the user's editor. Non-script assets double-click through xdg-open. - Resolution order: the new External Editor preference command (spawned detached as `<command> <file>`, flags allowed), else $VISUAL/$EDITOR in a new Terminal-panel tab (TUI editors work in-editor via the existing PTY widget), else xdg-open. - New `editor.external_editor` settings section (ExternalEditorPrefs) registered by EditorState, persisted with the preferences file, with a rich row in the Preferences window; registration covered by a unit test. Editor crate now depends on serde directly for its own sections. Saved edits flow back through the file watcher's live reload, including into a playing scene. GUI piece — needs an eye-check before promotion. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>