Bulk multi-select, sortable columns and country flags on Recommendations

A handful of changes that make the Recommendations page faster to work through:

• Multi-select with bulk resolve. Tick a row to select it; tick the column-header checkbox to select every row on the page. A floating bulk-action bar appears with "Resolve selected" and per-tab export buttons (selected IPs as a .txt for your WAF, selected rows as a CSV).
• Sortable columns. Click any column header to cycle through ascending → descending → unsorted. Works on every sortable column on every tab.
• Country flags. Country codes (US, DE, NL…) now render as emoji flags with a tooltip showing the full name. Tiny but makes geographic patterns jump off the page.