Design 3-A4i rung C0: IntersceneLma gains a null-safe ProfileSink (pattern-
consistent with the providers; zero overhead when unset). The production
prepareLMA overload emits setup+samples-weights / fx-pass-1 / WJtJ+reg+
normalize / fx-pass-2 samples (LMA path only - MB-vector calls excluded;
y+RMS tail = derived remainder). Two cross-cutting probes: the poseFxProvider
JNA roundtrip wall (all lean fx sites, incl. runLma's first-step
re-linearization) and the setupERS pair. CuasPoseRT routes the sink into
RtPoseProfile (6 new stages, printSummary extended).
Expected from one run of the same config: split prepare's ~16 ms/call into
JNA-roundtrip vs Java-CPU, sizing C1 honestly.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>