Debug view improvements, warp animation

* Add a visible frame one tile beyond the normal screen in debug mode.

* Fix the display of motion paths for mounted traps in debug mode.

* Add an animation for the warp trap.

tests/test_flow.py

@@ -131,6 +131,30 @@ def test_window_sized_once_for_tallest_level(make_game, tmp_path, monkeypatch):
     assert g.win_h == 4 * 32 + HUD_H
 
 
+def test_debug_view_adds_overscan_margin(tmp_path):
+    from game.game import Game, HUD_H
+    from game import settings as S
+    p = tmp_path / "d.yaml"
+    p.write_text("name: t\ntile_size: 32\ndebug: true\nmap: |\n  #####\n  #P.G#\n  #####\n")
+    g = Game([str(p)], str(tmp_path / "noassets"))
+    m = S.DEBUG_VIEW_MARGIN * 32
+    assert m > 0
+    # the level draws shifted into an enlarged play surface...
+    assert g.level.render_offset == (m, m)
+    assert g.world.get_size() == (g.level.width + 2 * m, g.level.height + 2 * m)
+    # ...and the fixed window budgeted the margin so it isn't clipped.
+    assert g.win_h == g.level.height + 2 * m + HUD_H
+
+
+def test_no_overscan_without_debug(tmp_path):
+    from game.game import Game
+    p = tmp_path / "n.yaml"
+    p.write_text("name: t\ntile_size: 32\nmap: |\n  #####\n  #P.G#\n  #####\n")
+    g = Game([str(p)], str(tmp_path / "noassets"))
+    assert g.level.render_offset == (0, 0)
+    assert g.world.get_size() == (g.level.width, g.level.height)
+
+
 def test_battery_visual_scales_by_pct(make_level):
     lvl = make_level(SIMPLE + "battery_pct: 4\n")
     assert lvl.battery_pct == 4