fix(agents): improve chat copying, selection and scrolling (#1905)

* fix(agents): improve chat transcript interactions

* fix(agents): recover images when regeneration fails

* test(agents): use the native copy shortcut on every host

src/ui/icons.tsx

@@ -224,6 +224,7 @@ const ICONS = {
   "search-history": "inline/searchHistory",
   filter: "general/filter",
   refresh: "general/refresh",
+  quote: "openidea/general/quote",
   settings: "general/settings",
   help: "openidea/general/help",
   "page-first": "openidea/general/pageFirst",

src/ui/openidea/general/quote.svg

@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M3 7H6V11H2.5V7.5C2.5 5.5 3.5 4 5.5 3.5M10 7H13V11H9.5V7.5C9.5 5.5 10.5 4 12.5 3.5" stroke="#6C707E" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>