feat: let canvas extensions select a section

blocks/canvas/editor-utils/blocks.js

@@ -1,4 +1,4 @@
-import { DOMParser as PMDOMParser, NodeSelection } from 'da-y-wrapper';
+import { DOMParser as PMDOMParser, NodeSelection, TextSelection } from 'da-y-wrapper';
 
 const NON_BLOCK_TABLE_NAMES = new Set(['metadata', 'section metadata', 'section-metadata']);
 
@@ -223,6 +223,36 @@ export function appendBlockRow(view, tablePos, rowDom) {
   view.dispatch(tr.scrollIntoView());
 }
 
+/** Doc range of each section, split on horizontal rules (see deleteSection). */
+export function getSectionRanges(view) {
+  const { doc, schema } = view.state;
+  const ranges = [];
+  let current = null;
+  doc.forEach((node, offset) => {
+    if (node.type === schema.nodes.horizontal_rule) {
+      current = null;
+      return;
+    }
+    if (!current) {
+      current = { from: offset, to: offset };
+      ranges.push(current);
+    }
+    current.to = offset + node.nodeSize;
+  });
+  return ranges;
+}
+
+/** Select a whole section and scroll it into view. */
+export function selectSection(view, sectionIndex) {
+  if (!view) return false;
+  const range = getSectionRanges(view)[sectionIndex];
+  if (!range) return false;
+  const { tr, doc } = view.state;
+  view.dispatch(tr.setSelection(TextSelection.create(doc, range.from, range.to)).scrollIntoView());
+  view.focus();
+  return true;
+}
+
 export function deleteSection(view, sectionIndex) {
   if (!view) return;
   const { doc, schema } = view.state;

blocks/canvas/ew-panel-extensions/iframe-protocol.js

@@ -1,4 +1,6 @@
 import { insertText, insertHTML, getEditorSelection } from './helpers.js';
+import { selectSection } from '../editor-utils/blocks.js';
+import { canvasBus } from '../utils/canvas-bus.js';
 import { getNx } from '../../../scripts/utils.js';
 import { getPostMessageTargetOrigin, isValidHref } from '../../shared/utils.js';
 
@@ -61,6 +63,25 @@ export async function setupIframeChannel({ iframe, hashState, getView, onClose }
       );
     }
 
+    // Navigation reuses the outline's own path — same blockIndex address, same
+    // scroll — rather than driving the view directly, so the outline highlight
+    // and doc state stay in step.
+    if (action === 'scrollToBlock') {
+      const ok = Number.isInteger(details?.blockIndex) && details.blockIndex >= 0;
+      if (ok) canvasBus.editorSelectState.emit({ blockIndex: details.blockIndex, source: 'plugin' });
+      channel.port1.postMessage({ action: 'scrollToBlockResult', details: { ok } });
+      return;
+    }
+
+    // Separate from navigation: a section range is the only way to reach section
+    // metadata, which getBlockPositions deliberately excludes from blockIndex.
+    // Leaves a replaceable range under sendHTML.
+    if (action === 'selectSection') {
+      const ok = editorView ? selectSection(editorView, details?.index) : false;
+      channel.port1.postMessage({ action: 'selectSectionResult', details: { ok } });
+      return;
+    }
+
     if (action === 'getSelection') {
       if (!editorView) {
         channel.port1.postMessage({ action: 'error', details: 'No editor view' });