Shrink ignores what cannot be seen; blank lines at a block's end go

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

client/js/text_editor.js

@@ -14,7 +14,7 @@ import { randomId } from './crypto.js';
 import { textBounds } from './page_model.js';
 import { TEXT_FRAME_WIDTH, TEXT_MARK } from './page_file.js';
 import { HOLD_MS, HOLD_SLACK_PX } from './pen_input.js';
-import { LEFT_GAP, LINE_HEIGHT, TOP_GAP, baselineOf, fontMetrics, layoutText } from './text_layout.js';
+import { LEFT_GAP, LINE_HEIGHT, TOP_GAP, baselineOf, fontMetrics, layoutText, trimTrailingBlankLines } from './text_layout.js';
 
 /** @typedef {import('./page_model.js').TextBlock} TextBlock */
 /** @typedef {import('./page_model.js').TextFont} TextFont */
@@ -206,7 +206,10 @@ export class TextEditor {
     this.field.setSelectionRange(block.text.length, block.text.length);
   }
 
-  /** Finish editing.  An empty block is removed. */
+  /**
+   * Finish editing.  The blank lines at the end go (Andy, 2026-10-14),
+   * and an empty block is removed.
+   */
   stop() {
     const block = this.block;
     if (!block) return;
@@ -215,6 +218,7 @@ export class TextEditor {
     this.field.hidden = true;
     this.mark.hidden = true;
     this.field.value = '';
+    trimTrailingBlankLines(block);
     if (block.text.trim() === '') this.target.removeText(block.id);
     else this.target.setText(block);
     this.target.endEdit?.(block.id);