fix(rules): charge clear-path tests the whole footprint for difficult terrain (SRD movement-position-and-distance-2.md: 'You can't run or charge across difficult terrain' + 'you can move only as fast as the most difficult terrain you occupy') - _charge_path_clear priced only the anchor cell, so a 2x2 creature with one trailing square in rubble charged freely; the move-descent footprint pricing is deferred (would rewrite the anchor-based Dijkstra cost field)

src/pf1e_simulator/combat.py

@@ -3999,14 +3999,17 @@ class CombatEngine:
         blocks movement, slows movement, or contains a creature (even an
         ally), you can't charge" - the straight Bresenham anchor line is the
         engine's model of that path, walked under the full-footprint gates
-        below.
+        below. Difficult terrain is tested over the WHOLE footprint, not
+        just the anchor cell (SRD "Movement, Position and Distance": "You
+        can't run or charge across difficult terrain" - a 2x2 creature with
+        one trailing square in rubble cannot charge).
         """
         prev = state.pos
         for pos in path:
-            if not self._cells_free(self._footprint_at(pos, state), state):
+            footprint = self._footprint_at(pos, state)
+            if not self._cells_free(footprint, state):
                 return False
-            terrain = self._grid.terrain_at(pos)
-            if terrain.move_cost is not None and terrain.move_cost > 1:
+            if self._footprint_touches_difficult(footprint):
                 return False
             if (
                 prev[0] != pos[0]