HUD: merge TimeDisplay into ImplantPanel (time/health/perception in one panel), remove dead tscn nodes, move HUD to InsertOverlay for D-051 bloom. Interaction prompt: convert from PanelContainer+StyleBoxFlat to Control with ImplantPanel+ImplantDataRow, fix panel height for 42px minimum. Tests updated for new scene structure and public API. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>