feat(edge-storage): add recursive folder deletion support

[marcusgrando]

Summary

• Add support for recursive folder deletion in the Object Storage file browser
• Users can now select folders via checkboxes (alongside files) and delete them, including all nested contents
• Individual folder deletion available through the row action menu (three-dot menu)
• Adaptive confirmation dialogs show context-aware messages for files-only, folders-only, and mixed selections

Motivation

Previously, users had to navigate into each folder and manually delete files page by page. There was no way to select or delete a folder and its contents in one operation. This change removes that friction.

How it works

Service layer (edge-storage-service.js)

New deleteRecursiveBucketFolder(bucketName, prefix, onProgress) method that:

1. Lists all objects under the prefix using all_levels=true, paginating through all pages first (collecting keys into an array)
2. Then deletes each object one by one with progress tracking

This two-phase approach (list-all-then-delete) avoids skipping objects that would happen if we interleaved listing and deleting on a mutating collection.

Composable layer (useEdgeStorage.js)

deleteMultipleFiles now accepts Array<{ name, isFolder }> instead of string[]:

• Separates items into files and folders
• Files go through the existing deleteMultipleEdgeStorageBucketFiles
• Folders go through the new deleteRecursiveBucketFolder
• Results are aggregated with unified toast messages ("items" instead of "files")

New refs (currentProcessStep, discoveredItemsCount, totalDeleteItems) support the two-phase progress UI.

UI changes

• folder-list.vue: Folder rows now have checkboxes, showActions allows the action menu on folders, Download and Move bulk buttons are hidden when any folder is in the selection
• ListView.vue: Row actions use visibleAction to show only Delete for folders (no Download/Rename/Move). New handleDeleteFolder for single-folder deletion. handleDeleteSelectedItems builds adaptive dialog messages based on selection composition
• ProgressCard.vue: Shows "Preparing delete list..." with an indeterminate progress bar during the listing phase, then switches to percentage-based progress during deletion

Test plan

• Select a single file → Delete → existing behavior unchanged
• Select multiple files → Delete → existing bulk delete unchanged
• Select a single folder via checkbox → Delete → recursive delete with two-phase progress
• Delete a folder via row action menu → confirmation dialog → recursive delete
• Select files + folders → Download and Move buttons disappear, Delete remains
• Mixed selection delete → dialog shows "X file(s) and Y folder(s)" message
• Folder-only selection → folder-specific warning text in dialog
• Delete folder with nested subfolders → all contents removed at all depths
• Delete empty folder → folder disappears after refresh
• Large folder (100+ objects) → progress card shows listing phase, then percentage delete
• Partial failure → toast reports partial completion
• File row action menu → shows Download, Rename, Move, Delete
• Folder row action menu → shows only Delete