feat(sidebar): add dialogue selection and copying (#238)

src/renderer/style.css

@@ -3690,6 +3690,7 @@ body.subtitle-sidebar-embedded-open #subtitleSidebarContent {
 }
 
 .subtitle-sidebar-timestamp {
+  user-select: none;
   font-size: 0.72em;
   font-weight: 600;
   font-variant-numeric: tabular-nums;
@@ -3712,6 +3713,8 @@ body.subtitle-sidebar-embedded-open #subtitleSidebarContent {
 }
 
 .subtitle-sidebar-text {
+  user-select: text;
+  cursor: text;
   white-space: pre-wrap;
   line-height: 1.5;
   font-size: 1em;