Provide managers with a dedicated page to analyze hold lots across all stations.
Extends existing service functions (get_hold_detail_summary, get_hold_detail_lots,
get_wip_matrix) with optional parameters for backward compatibility, adds one new
function (get_hold_overview_treemap), and registers the page in the portal navigation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>