When >= 2 entries are selected, ContextRail switches to a bulk panel:
- Count badge showing number of selected entries
- Assign tag: path input + Add button; applies assignTag() to all selected
UIDs sequentially; shows done/error feedback; refreshes tag tree on success
- Add to collection: select populated from listCollections(); applies
addEntryToCollection() to all UIDs (skips already-present errors)
- Delete: window.confirm with count; deletes sequentially; partial failures
are skipped; calls onBulkDeleted() to remove all deleted entries from the
list in one update
- Single-entry Tags/Delete/Collections sections gated with !isBulk to prevent
flash of stale single-entry UI during the async auto-snap effect
- Transient bulk state (tag input, coll selection, delete spinner) resets
whenever selectedUids changes
- CSS: bulk-count, bulk-coll-row/select, tag-add-btn:disabled
