testdata: seed sandbox overlap base

roodboi · roodboi · commit cb9885b6d482 · 2026-03-26T14:27:35.000-04:00
diff --git a/_test_data/sandbox/overlap/shared.md b/_test_data/sandbox/overlap/shared.md
@@ -0,0 +1,11 @@
+# Same-File Overlap
+
+## Section A
+
+Parent branch owns this section and introduces the file.
+
+## Section B
+
+This section will be edited by the child branch.
+
+Marker: 00e3fde
