Add more annotation tools to edit mode (text, drawings)

[roiguri]

Request

Expand the edit mode toolbar with additional annotation tools beyond the current highlight and signature options.

Proposed Tools

• Text box — place a resizable text annotation directly on the PDF page
• Freehand drawing — pen/pencil tool for freehand markup
• Shapes — rectangle, ellipse, arrow overlays
• Sticky note — small collapsible comment anchored to a page position

Current Architecture

The edit toolbar is in src/components/pdf/EditToolbar.tsx. New tool types would need to be added to:

• AnnotationType union in src/store/slices/annotationSlice.ts
• src/components/pdf/AnnotationOverlay.tsx — rendering and interaction logic per type
• src/components/pdf/EditToolbar.tsx — toolbar buttons
• src/lib/pdf-utils.ts — embedAnnotationsInPdf export logic for each new type

Notes

• Each tool should support drag-to-reposition and delete (already handled generically in DraggableAnnotation)
• Text boxes should support inline editing on double-click
• Export (embedAnnotationsInPdf) must embed new annotation types into the PDF bytes using pdf-lib