feat(replay): the whole replay chain is C++, including the sink

The sae_kpn module has not compiled since the AR-007/AR-008 tracker redesign,
and was switched off at the build rather than patched because the fix is a
restructuring. Two failures, one cause.

It did not compile: `add_face_tracker` built FaceTrackerFunc from a Config
alone, and the tracker has required a TrackRegistry and a calibration since
association moved into probability space.

And presence was rebuilt in Python. `replay.py::build_minimal` merged
per-frame detections into windows by annealing gaps, which is what the
pipeline did before AR-012. The sink builds a window from a TrackRegistry
claim instead — the extent of a track an actor owned, starting when they
appeared rather than when recognition first succeeded. Those answer different
questions, so every sweep was tuning against a contract the shipped code had
stopped honouring.

Both follow from the seam being a factory per node. The chain has a
construction order — the matcher fits the calibration, the registry needs a
discounter built from it, the tracker needs both, and the sink needs the
registry's claims — and independent factories cannot express it, so the
tracker kept being built against a signature that no longer existed. One
`add_pipeline` mirrors main.cpp exactly and is now the only way to build the
chain, so the ordering cannot be got wrong again from Python. DP-001 is the
requirement behind it: a replay harness is a front-end, and its job is to
supply frames and read the result, not to re-derive presence.

Lifetimes needed a home. ResultSinkFunc holds `const Config&` and
`std::atomic<bool>&`, which under main() are locals in a frame outliving the
pipeline; there is no such frame when the network is built and torn down from
Python. ReplaySession owns both for the network's lifetime, keyed by network
and released explicitly — a sweep builds one network per replay and the sink
retains every annotation, so holding them forever would grow with films x
configs. Getting this wrong presented as an empty output_path: the sink
announced `[result_sink] writing ` and wrote nothing.

test_sae_kpn.py is ported rather than left behind. It called all three removed
factories and asserted on SceneAnnotations read back per frame; neither half
survives, so it now waits on pipeline_done and asserts on the file the sink
writes. Verified against gallery_lvface.h5: three frames through the real
chain, timestamps 0/1/2, truth file written. EOF is a control token the sink
flushes on and does not record, so three inputs give three frames, never four.

SAE_BUILD_KPN_BINDINGS goes back to ON.

TRACES: VR-011, VR-002 | DP-001 | PR-002

scripts/optimizer/optimize.py

@@ -17,7 +17,7 @@ point from the trajectory (--trajectory).
 Usage:
   python scripts/optimizer/optimize.py --manifest films.json \
       --gallery gallery_arcface_w600k_r50.json \
-      --params prob_threshold:0.5:0.999 anneal_sec:1:30 track_alpha:0:1 \
+      --params prob_threshold:0.5:0.999 ownership_logodds:0.5:4 track_alpha:0:1 \
       --popsize 20 --maxiter 25 --trajectory traj.json
 """
 from __future__ import annotations
@@ -239,7 +239,7 @@ def main():
             rec = {"eval": evals[0], "config": cfg, **m, "t": round(time.time() - t0, 1)}
             traj.append(rec)
             print(f"[opt] eval {evals[0]:3d}  thr={cfg['prob_threshold']:.2f} "
-                  f"ann={cfg.get('anneal_sec', float('nan')):.0f}  → "
+                  f"own={cfg.get('ownership_logodds', float('nan')):.2f}  → "
                   f"F1={m['f1']*100:.1f}% P={m['precision']*100:.1f}% R={m['recall']*100:.1f}% "
                   f"agree={m.get('agreement', 0)*100:.1f}% misID={m.get('FPI_misid', 0)}",
                   file=sys.stderr)