Keep the dense landmarks behind each eye reading, packed

The 106 points the eye boxes were cut from, stored beside the reading as
16-bit fixed point over the frame: 424 bytes a face, a seventh of a pixel
on a 6000-pixel frame, where f16 at the same size would have been six.
Derived data like the embedding, kept for the same reason — it cost a
fetch and a model run, and the next per-face pass should run from the
catalog. Shards carry it; a peer's shard from before it is still read.

core/dr-face/examples/eyes.rs

@@ -64,7 +64,7 @@ fn main() {
                 .read(px, w, h, d.bbox, &d.landmarks)
                 .expect("read eyes");
             let ms = t.elapsed().as_secs_f64() * 1e3;
-            let Some(r) = reading else {
+            let Some((r, lm)) = reading else {
                 println!("  [{i}] nothing to cut, skipped");
                 continue;
             };
@@ -84,23 +84,18 @@ fn main() {
             );
             if let Some(dir) = &dump {
                 // The same crops `EyeModels::read` cut, cut again for the
-                // sheet: the reading itself carries numbers, not pixels.
-                if let Some(lm) = models
-                    .landmarks
-                    .landmarks(px, w, h, d.bbox)
-                    .expect("landmarks")
-                {
-                    for (name, contour) in [("right", lm.right_eye()), ("left", lm.left_eye())] {
-                        if let Some(patch) =
-                            align::eye_box(&contour).and_then(|b| align::eye_patch(px, w, h, b))
-                        {
-                            write_ppm(
-                                &dir.join(format!("{stem}-{i}-{name}.ppm")),
-                                patch.pixels(),
-                                align::EYE_PATCH_WIDTH,
-                                align::EYE_PATCH_HEIGHT,
-                            );
-                        }
+                // sheet from the landmarks it handed back: the reading itself
+                // carries numbers, not pixels.
+                for (name, contour) in [("right", lm.right_eye()), ("left", lm.left_eye())] {
+                    if let Some(patch) =
+                        align::eye_box(&contour).and_then(|b| align::eye_patch(px, w, h, b))
+                    {
+                        write_ppm(
+                            &dir.join(format!("{stem}-{i}-{name}.ppm")),
+                            patch.pixels(),
+                            align::EYE_PATCH_WIDTH,
+                            align::EYE_PATCH_HEIGHT,
+                        );
                     }
                 }
                 if let Some(head) = align::head_views(px, w, h, &d.landmarks) {