docs(changelog): record undefined filter versioning

Author: Ralph Küpper

changelog.d/8740-guarded-undefined-method-param.md

@@ -0,0 +1,11 @@
+Versioned eligible instance methods for an exact `undefined` optional argument.
+The public boxed-ABI wrapper validates the live argument bits once and sends only
+that value to a private specialized body; functions and every other falsey or
+non-callable value retain the ordinary JavaScript path. Mutation, closure capture,
+async/generator bodies, and oversized methods are conservatively excluded.
+
+This removes the per-entity optional-filter truthiness and callback arm from
+codehz/ecs's 10k-entity accumulation loop. On an Apple M1 Mac mini, 11
+alternating process pairs measured 0.179851 ms versus 0.195838 ms on the exact
+parent, an 8.126% median paired improvement with 11/11 wins and all output
+oracles passing.