[luis-godinho]

Adds data deletion operations (unindex and remove) at study, series, and instance level, matching legacy Dicoogle webapp functionality.

• Add unindex() and remove() methods to DicoogleService
• Add uri field to Image type, populated from search results
• Create ConfirmActionDialog component with distinct visual treatment for unindex (amber/warning) vs remove (red/destructive)
• Create useEntryActions hook to manage URI collection, confirmation state, API calls, and search refresh
• Add admin-only action buttons (eraser/trash icons) to StudyList, SeriesViewer, and ImageList
• "Remove" operation unindexes first then deletes files, matching legacy behavior
• Fix event propagation in Dialog and ImageActions to prevent parent click handlers from firing