fix(ui): mobile capture sticky, post-delete focus, inline markdown

- Capture bar stays visible on mobile via sticky positioning (#25)
- Cursor moves to adjacent entry after delete instead of resetting (#24)
- Inline expansion renders styled markdown via .exp-body.md selectors (#23)

web/app.js

@@ -1317,9 +1317,13 @@
     },
 
     async deleteEntity(id) {
+      const prevIdx = state.selectedIndex;
       await api.deleteEntity(id);
       await loadEntities();
       await loadTags();
+      if (state.entities.length > 0) {
+        selectEntity(Math.min(prevIdx, state.entities.length - 1));
+      }
       showToast('deleted');
     },