Real per-scene file I/O inside the measured loop (the honest RT test, and the
production shape: 4 reader threads = the 4xSATA-2 device groups of 4
consecutive sensors). New CuasSceneFeeder parses the single-strip 16-bit TIFF
layout ONCE from file #1 (strip@557, 656640 B, big-endian, telemetry row 0 -
verified constant over the whole segment and bit-exact vs the production
ImagejJp4Tiff reader), then preads raw strip bytes straight into the native
pinned u16 staging (PosixIo/libc - the kernel's read IS the pinned write,
half the pinned-write bytes of the float path). The GPU converts (byte-swap)
+ applies the borrowed per-scene Row/Col (prior scales snapshotted at
creation, exact double chain) + two-map conditions in ONE kernel
(condition_lwir_u16, native 84d7ab6) - bit-identical to the preload path by
the u16_cond case, so the Done-line byte-identity gate carries over.

Cold-read honesty: posix_fadvise(DONTNEED) after every file - reruns never
replay the page cache (the production RAM-based dual-port SATA feeder always
serves NEW frames). Cold bench: 4 threads 4.4/5.4/7.3 ms/scene p50/p95/max -
hidden under the ~12 ms DP entry via the D5 overlap, which now awaits the
in-flight read (kicked one scene ahead at collect-safe points, keeping the
one-scene staging slack contract).

Arrival moderation (Andrey 07/18): in paced (pose_pace) mode the feeder is
armed with the same 60 Hz epoch grid - the DATA, not just the loop, arrives
at 60 Hz; the overlap then fires only when the next read already landed
(never parks inside the DP window), i.e. exactly when running behind.

New saved checkbox curt.pose_feed16 (default ON) selects the feeder; OFF =
the legacy float preload (A/B). CPU-oracle fallback (heap reads + the exact
preload float chain) covers cond_gpu OFF and any native failure. Stage0
42/42; mvn package PASS.
Co-authored-by: Claude Fable 5 <claude-fable-5@anthropic.com>