Improve annotations (#5919)

* Text box/notes movement improvements ✅
* Fix the issue where hiding, then showing annotations looses progress ✅
* Fix the issue where hidig/showing annotations jumps you back up to the
top of your open document ✅
* Support ctrl+c and  ctrl+v and backspace to delete ✅
* Better handling when moving to different tool from annotate ✅
* Added a color picker eyedropper button  ✅
* Auto-switch to Select after note/text placement, so users can quickly
place and type ✅

frontend/src/core/contexts/ViewerContext.tsx

@@ -77,7 +77,7 @@ function useImmediateNotifier<Args extends unknown[]>() {
  * - Actions call EmbedPDF APIs directly through bridge references
  * - No circular dependencies - bridges don't call back into this context
  */
-interface ViewerContextType {
+export interface ViewerContextType {
   // UI state managed by this context
   isThumbnailSidebarVisible: boolean;
   toggleThumbnailSidebar: () => void;