perf: batch springs

src/spring.luau

@@ -1,3 +1,4 @@
+local batch = require "./batch"
 local graph = require "./graph"
 type Node<T> = graph.Node<T>
 type SourceNode<T> = graph.SourceNode<T>
@@ -263,6 +264,8 @@ local function step_springs(dt: number)
 end
 
 local function update_spring_sources()
+    graph.bump_update_id()
+    batch(function()
         for data, output in springs do
             local x0_123, x1_123, v_123,
             x0_456, x1_456, v_456 =
@@ -285,9 +288,9 @@ local function update_spring_sources()
                 output.cache = vec6_to_type[typeof(data.source_value)](x0_123, x0_456)
             end
 
-        graph.bump_update_id()
             update_descendants(output)
         end
+    end)
 end
 
 return function()