feat(hud): estimated kills - each loot event = 1 kill

- Every loot batch (You received [item]) = 1 estimated kill
- Label shows 'EST. KILLS' to indicate estimated value
- Simple and consistent kill tracking

ui/hud_overlay.py

@@ -333,9 +333,9 @@ class HUDOverlay(QWidget):
         # Row 1: Damage & Kills & Globals
         row1 = QHBoxLayout()
         
-        # Kills
+        # Kills (Estimated)
         kills_layout = QVBoxLayout()
-        kills_label = QLabel("💀 KILLS")
+        kills_label = QLabel("💀 EST. KILLS")
         kills_label.setStyleSheet("font-size: 10px; color: #888888;")
         kills_layout.addWidget(kills_label)
         

ui/main_window.py

@@ -958,9 +958,7 @@ class MainWindow(QMainWindow):
             if item_name == 'Universal Ammo':
                 return
             
-            # Kill tracking: Only count on non-Shrapnel loot
-            # Shrapnel-only mobs will be undercounted, but avoids overcounting
-            if item_name != 'Shrapnel':
+            # Estimated Kills: Every loot event = 1 mob killed
             self.hud.update_stats({'kills_add': 1})
             
             # Queue database write for main thread (SQLite thread safety)