Rewrite tx list with innerHTML, fix scrollbar overlay and overflow

- Rebuilt tx list rendering using innerHTML instead of createElement
- scrollbar-gutter: stable on body to prevent content shift
- max-width:42ch instead of width:42ch to prevent horizontal overflow
- overflow-x:hidden on body and #app

src/popup/styles/main.css

@@ -16,4 +16,6 @@
 body {
     width: 396px;
     overflow-x: hidden;
+    overflow-y: auto;
+    scrollbar-gutter: stable;
 }