Read each face's eyes, and whether sunglasses hide them

Two MIT classifiers from the same author as the reference pipeline's
whole-body detector: OCEC answers P(open) for one 40×24 eye, SGC
P(sunglasses) for a 48×48 head. Both load in tract once their batch
dimension is pinned by tools/fix-face-model-shapes.sh, like the embedder.

The crops come through the same fitted similarity the aligned face does,
so an eye window is a constant in template units rather than a second
warp, and a tilted head yields an upright eye. Measured on 60 proxies
from the reference library: the eye window plateaus at 22×11, the S
variant beats M and L (which overfit their own domain), and for
sunglasses the aligned face beats a head framing but the higher of the
two catches 11 of 12 pairs against 9 for either alone.

The reading keeps both eyes and the sunglasses number apart, because a
wink averages to the least informative value and a lens of dark glass
draws a confident answer from the eye classifier — over a woman in
sunglasses it read the right eye 0.97 open. Sunglasses take precedence,
and a face behind them is neither open nor a blink.

core/dr-face/Cargo.toml

@@ -30,6 +30,10 @@ required-features = ["inference"]
 name = "faces"
 required-features = ["inference"]
 
+[[example]]
+name = "eyes"
+required-features = ["inference"]
+
 [features]
 # Nothing on by default, and in particular **no `embedded-model`**: the weights
 # are not a build input and never become one (docs/faces.md §2.2). A feature