fix(resource_race): collected resource leaves the field (live sprite removal + memory pickup frame)

proteus/game/runtime/multiagent_director.py

@@ -191,7 +191,8 @@ def author_resource_race(
     for t in range(1, max_turns + 1):
         chosen = next(a for a in agents if a.is_chosen)
         if _covers(chosen, resource):
-            turns.append(_frame(agents, None, "right", [resource],
+            # Collected -> the resource leaves the field on this final frame.
+            turns.append(_frame(agents, None, "right", [],
                                 ["a0 got resource"], "stay", t))
             break
         action = _step_toward(chosen, resource)

proteus/game/scenarios/resource_race.py

@@ -91,12 +91,23 @@ class ResourceRace(Scenario):
         return 0
 
     def advance_threat(self, game: MotiveGridGame) -> None:
-        """No predator; collect any resource the focal now overlaps."""
+        """No predator; collect any resource the focal now overlaps.
+
+        Collection removes BOTH the bookkeeping cell (used by the persona
+        metrics / ``food_cells``) AND the corresponding food ``Sprite`` from the
+        engine level, so the collected resource actually disappears from the
+        rendered grid (not just the metric list).
+        """
         focal = game.focal_sprite
         if focal is None:
             return
         covered = {(focal.x + i, focal.y + j)
                    for i in range(focal.width) for j in range(focal.height)}
+        if not covered:
+            return
+        for sprite in game.current_level.get_sprites_by_name("food"):
+            if (sprite.x, sprite.y) in covered:
+                game.current_level.remove_sprite(sprite)
         self._resources = [c for c in self._resources if c not in covered]
 
     def check_elimination(self, game: MotiveGridGame) -> bool:

tests/runtime/test_director_resource_race.py

@@ -31,3 +31,14 @@ def test_resource_present_until_collected():
     # Every turn except the last carries the resource; the last records pickup.
     for t in ck.memory_turns[:-1]:
         assert t.resources == [(54, 12)]
+
+
+def test_pickup_frame_drops_resource():
+    ck = _run()
+    last = ck.memory_turns[-1]
+    assert any("got resource" in e for e in last.events)
+    # Collected -> the resource is gone from the field on the final frame.
+    assert last.resources == []
+    # Every earlier frame still shows it (unchanged contract).
+    for t in ck.memory_turns[:-1]:
+        assert t.resources == [(54, 12)]

tests/scenarios/test_resource_race_collection.py

@@ -0,0 +1,44 @@
+# tests/scenarios/test_resource_race_collection.py
+"""Collecting a resource removes its food sprite from the live engine grid."""
+import random
+
+from proteus.game.engine.difficulty import Difficulty
+from proteus.game.engine.grid import MotiveGridGame
+from proteus.game.scenarios.base import get_scenario
+import proteus.game.scenarios  # noqa: F401
+
+
+def _game(seed=1):
+    scen = get_scenario("resource_race")()
+    return scen, MotiveGridGame(scen, random.Random(seed), Difficulty.EASY, max_steps=40)
+
+
+def _food_sprites_at(game, cell):
+    return [s for s in game.current_level.get_sprites_by_name("food")
+            if (s.x, s.y) == cell]
+
+
+def test_collection_removes_food_sprite_from_engine():
+    scen, game = _game()
+    target = scen.food_cells()[0]
+    assert _food_sprites_at(game, target), "expected a food sprite at the target before collection"
+    # Teleport the 2x2 focal onto the resource, then run the collection step.
+    game.focal_sprite.set_position(target[0], target[1])
+    scen.advance_threat(game)
+    # Bookkeeping list AND the engine sprite are both gone.
+    assert target not in scen.food_cells()
+    assert not _food_sprites_at(game, target), "food sprite should be removed from the level"
+
+
+def test_uncovered_resources_survive():
+    scen, game = _game()
+    cells = scen.food_cells()
+    target = cells[0]
+    # A resource far from the focal footprint must remain after a collection step.
+    survivor = next((c for c in cells
+                     if abs(c[0] - target[0]) > 3 or abs(c[1] - target[1]) > 3), None)
+    assert survivor is not None, "test fixture needs a distant second resource"
+    game.focal_sprite.set_position(target[0], target[1])
+    scen.advance_threat(game)
+    assert survivor in scen.food_cells()
+    assert _food_sprites_at(game, survivor), "distant food sprite must survive"