ux: unify Monaco scrollbar width to 8px across pre-diff entry and post-diff view

The home-page paste boxes (pages/index.vue) used Monaco's stock ~14-px
vertical scrollbar, while the diff viewer's modified pane had been
narrowed to 8-px via inline createDiffEditor options. Visual weight of
the right-edge scrollbar differed between the two pages — chunky on
the entry page, slim on the diff page.

Move the scrollbar config into the shared getMonacoEditorDefaultOptions
in helpers/utils.ts:
  scrollbar: {
    useShadows: false,
    verticalScrollbarSize: 8,
    horizontalScrollbarSize: 8,
    verticalSliderSize: 8,
    horizontalSliderSize: 8,
  }

Both pages spread these defaults, so the entry boxes now get the same
slim 8-px scrollbar that the diff viewer's modified pane shows. The
diff editor's per-side updateOptions still overrides this for the
original pane (verticalScrollbarSize:0 to hide it entirely while
intra-diff sync drives both panes from the modified scrollbar).

Removed the now-redundant explicit scrollbar block from diff.vue's
createDiffEditor call — the spread defaults cover it.

Author: mxhob1

helpers/utils.ts

@@ -93,6 +93,19 @@ export function getMonacoEditorDefaultOptions(theme: string): any {
     selectionHighlight: false,
     renderLineHighlight: 'none',
     inlineSuggest: { enabled: false },
+    /* Slim 8-px scrollbars on every Monaco editor that consumes these
+     * defaults — the home page paste boxes AND the diff editor below.
+     * Without this, the home editors get Monaco's stock ~14-px bars
+     * which look chunky next to the diff page's 8-px modified-pane
+     * scrollbar. Consistency across pre-diff (entry) and post-diff
+     * (view) keeps the visual weight of vertical chrome the same. */
+    scrollbar: {
+      useShadows: false,
+      verticalScrollbarSize: 8,
+      horizontalScrollbarSize: 8,
+      verticalSliderSize: 8,
+      horizontalSliderSize: 8,
+    },
   }
 }
 

pages/diff.vue

@@ -297,13 +297,9 @@ export default Vue.extend({
               // change overview rather than a redundant scrollbar.
               overviewRulerBorder: false,
               overviewRulerLanes: 3,
-              scrollbar: {
-                useShadows: false,
-                verticalScrollbarSize: 8,
-                horizontalScrollbarSize: 8,
-                verticalSliderSize: 8,
-                horizontalSliderSize: 8,
-              },
+              /* scrollbar settings (8-px slim bars) inherited from
+               * getMonacoEditorDefaultOptions(); per-side overrides
+               * below tune width=0 on the hidden original pane. */
               renderLineHighlight: 'none',
               renderOverviewRuler: true,
             }