Editor: view-scoped Extract-to-Dataset for inline and self-defined data

docs/architecture/03-modal-system.md

@@ -75,7 +75,10 @@ export interface ModalConfig {
   component: ComponentType<any>; // the body rendered inside the shell
 
   /** Initialize transient modal state when it opens. `arg` carries an
-   *  optional sub-target (e.g. a dataset id for chartBuilder/extract). */
+   *  optional sub-target (e.g. a dataset id for chartBuilder/datasets). OMIT
+   *  when a service seeds the store *before* `openModal` — Extract is seeded by
+   *  `services/extract-action` from the editor cursor, and an `init` here would
+   *  re-read and clobber that view-scoped capture. */
   init?: (arg?: string) => void;
 
   /** Serializable snapshot of in-progress edits, used to detect unsaved