rename gauntlet→candy_survival + rewrite Candy Survival per boss design

- Rename enum GAUNTLET→CANDY_SURVIVAL, all gauntlet_*→candy_survival_*
- Rename files: gauntlet_manager→candy_survival_manager, candy_cannon→candy_survival_npc, gauntlet.tscn→candy_survival.tscn
- Rewrite candy_survival_manager.gd: blueprints, candy stack, Mekton delivery, Sugar Rush, knock/ghost charges, sticky-as-wall
- Update player_movement_manager.gd: smack→knock system, ghost integration
- All Candy Survival issues (#54-57, #65-70) retitled per boss design
- Shared managers (goals_cycle, goal, player_race, playerboard, turn) untouched

scenes/player.gd

@@ -1140,11 +1140,11 @@ func _find_valid_drop_position() -> Vector2i:
 		var item_cell = Vector3i(pos.x, 1, pos.y)
 		if enhanced_gridmap.get_cell_item(item_cell) == -1:
 			if not is_position_occupied(pos):
-				# Gauntlet Mode explicit overrides
+				# Candy Survival explicit overrides
 				var gm = null
-				var main_gauntlet = get_tree().root.get_node_or_null("Main")
-				if main_gauntlet and main_gauntlet.get("gauntlet_manager"):
-					gm = main_gauntlet.gauntlet_manager
+				var main_candy_survival = get_tree().root.get_node_or_null("Main")
+				if main_candy_survival and main_candy_survival.get("candy_survival_manager"):
+					gm = main_candy_survival.candy_survival_manager
 				if gm and gm.is_active:
 					if pos.x == 0 or pos.x == gm.ARENA_COLUMNS - 1 or pos.y == 0 or pos.y == gm.ARENA_ROWS - 1:
 						continue