Vacuum: one selection for pick-up and blow, full list while Ctrl is held (t20)

With anything selected a drag takes only the selection; with nothing
selected it takes what you click. Right click blows the selected materials
in the bag. Holding Ctrl lists every material found so far under "Not in
bag". Selections stay when materials run out; Clear button, clicking the
only selected row, or gamepad B clears.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DESIGN.md

@@ -243,6 +243,13 @@ above, including:
   the hand (this settles the old t18 question), and an empty hand blows nothing and says so.
   Picking something up fills an empty hand, never a chosen one. One tool, no menu; R and F do
   nothing special with the Vacuum. The owner mostly uses it to collect ore and fuel and feed furnaces.
+  Follow-up the same day: the hand became **one selection for both** picking up and blowing out,
+  because there was no way to choose several materials to pick up, or ones not in the bag yet. With
+  anything selected, a drag takes only the selection wherever it starts; with nothing selected it
+  takes what you click. Holding Ctrl lists every material found so far below a "Not in bag" divider
+  (no menu). Selected materials stay selected when they run out, and picking up never selects
+  anything (both reverse the first t20 version). Clear: a button in the bag, clicking the only
+  selected row, or gamepad B.
 
 - **Fog of war also reveals the ground around the bot (t17, 2026-10-24).** About 20 grains in every
   direction, through rock, fully clear with a soft edge. Line of sight alone hid everything inside