feat(adr-185): P1 AETHER bindings (wifi_densepose.aether) + parity harness

Bind the ADR-024 contrastive CSI embedding surface into the wheel behind
a gated [aether] extra / Cargo `aether` feature, per ADR-185 section 3.2.

Surface (bound against the REAL code at HEAD, not the ADR wishlist):
- AetherConfig       -> EmbeddingConfig {d_model,d_proj,temperature,normalize}
- CsiAugmenter       -> augment_pair(window, seed)
- EmbeddingExtractor -> embed(csi): 128-dim L2-normed, GIL-released
- info_nce_loss, cosine_similarity (module fns)

ADR-185 section 3.2 also names aether_loss/VICReg components,
alignment_metric, uniformity_metric, forward_dual, and vicreg_* config
fields. None exist in embedding.rs at HEAD, so they are intentionally NOT
bound (a Rust-side gap, not a binding gap) rather than fabricated.

Parity (section 4.1, release-blocking): committed fixture
aether_input.json -> native Rust reference (tests/aether_parity.rs, calls
sensing-server EmbeddingExtractor directly) locks
tests/golden/aether_embedding.sha256; pytest (tests/test_aether.py) runs
the same fixture through the binding and asserts the identical SHA-256 of
the LE f32 bytes. Both pass.

Verified: cargo test --features aether --test aether_parity -> 2/2 pass;
maturin develop --features aether + pytest tests/test_aether.py -> 9/9
pass; default cargo build clean with 0 sensing-server refs in the dep
graph (gate keeps the base wheel lean).

HONEST WHEEL-SIZE FINDING (ADR-185 section 9 / Open Q 11.1, unresolved):
wifi-densepose-sensing-server is an Axum/tokio crate whose tokio/axum/
worldgraph/ruvector deps are NON-optional (only mqtt/matter are
features), so default-features=false does NOT drop them. An [aether]
wheel therefore links the full server tree and BREAKS the ADR-117 section
5.4 <=5 MB budget. The fix is the ADR-sanctioned hoist of embedding.rs
(+ its graph_transformer/sona siblings) into a leaf crate so the wheel
links pure compute only -- a change INSIDE wifi-densepose-sensing-server,
owned by another agent this session, so deferred as a required
pre-release follow-up. P1 binds real code and proves parity today; the
hoist is a wheel-size optimization, not a functional blocker.

Note: building required initializing the worldgraph/rufield/ruvector
submodules (absent in the fresh worktree).

python/tests/aether_parity.rs

@@ -0,0 +1,99 @@
+//! ADR-185 §4.1 — AETHER bit-for-bit parity: native-Rust reference half.
+//!
+//! Produces the golden 128-dim embedding by calling the canonical
+//! `wifi-densepose-sensing-server::embedding` code DIRECTLY (no PyO3),
+//! for the committed `tests/golden/aether_input.json` fixture, and locks
+//! its SHA-256 into `tests/golden/aether_embedding.sha256`.
+//!
+//! The pytest half (`tests/test_aether.py`) independently runs the same
+//! fixture through the Python binding and asserts the identical hash —
+//! together they prove the binding is byte-identical to native Rust.
+//!
+//! Regeneration (only when the Rust subsystem intentionally changes):
+//! delete `tests/golden/aether_embedding.sha256` and re-run
+//! `cargo test --features aether`.
+#![cfg(feature = "aether")]
+
+use std::fs;
+use std::path::PathBuf;
+
+use sha2::{Digest, Sha256};
+use wifi_densepose_sensing_server::embedding::{EmbeddingConfig, EmbeddingExtractor};
+use wifi_densepose_sensing_server::graph_transformer::TransformerConfig;
+
+fn golden_dir() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("tests")
+        .join("golden")
+}
+
+fn load_input() -> Vec<Vec<f32>> {
+    let raw = fs::read_to_string(golden_dir().join("aether_input.json"))
+        .expect("read aether_input.json fixture");
+    let rows: Vec<Vec<f64>> = serde_json::from_str(&raw).expect("parse aether_input.json");
+    rows.into_iter()
+        .map(|row| row.into_iter().map(|x| x as f32).collect())
+        .collect()
+}
+
+/// Build the extractor identically to the Python binding's default
+/// construction: `AetherConfig()` + `EmbeddingExtractor(n_subcarriers=56, cfg)`.
+fn embed_native(input: &[Vec<f32>]) -> Vec<f32> {
+    let e_config = EmbeddingConfig {
+        d_model: 64,
+        d_proj: 128,
+        temperature: 0.07,
+        normalize: true,
+    };
+    let t_config = TransformerConfig {
+        n_subcarriers: 56,
+        n_keypoints: 17,
+        d_model: 64,
+        n_heads: 4,
+        n_gnn_layers: 2,
+    };
+    let mut ext = EmbeddingExtractor::new(t_config, e_config);
+    ext.extract(input)
+}
+
+fn sha256_le(embedding: &[f32]) -> String {
+    let mut hasher = Sha256::new();
+    for &x in embedding {
+        hasher.update(x.to_le_bytes());
+    }
+    hasher
+        .finalize()
+        .iter()
+        .map(|b| format!("{b:02x}"))
+        .collect()
+}
+
+#[test]
+fn native_embedding_is_128_dim_unit_norm() {
+    let emb = embed_native(&load_input());
+    assert_eq!(emb.len(), 128, "AETHER embedding must be 128-dim");
+    let norm: f32 = emb.iter().map(|x| x * x).sum::<f32>().sqrt();
+    assert!(
+        (norm - 1.0).abs() < 1e-4,
+        "embedding must be L2-normalized, got norm={norm}"
+    );
+}
+
+#[test]
+fn native_embedding_matches_committed_golden() {
+    let emb = embed_native(&load_input());
+    let got = sha256_le(&emb);
+    let path = golden_dir().join("aether_embedding.sha256");
+    match fs::read_to_string(&path) {
+        Ok(expected) => assert_eq!(
+            got,
+            expected.trim(),
+            "native AETHER embedding hash drifted from committed golden \
+             (intentional? delete the .sha256 and regenerate)"
+        ),
+        Err(_) => {
+            fs::write(&path, &got).expect("write golden sha256");
+            panic!("no committed golden found; wrote {got}. Re-run to verify parity.");
+        }
+    }
+}

python/tests/golden/aether_embedding.sha256

@@ -0,0 +1 @@
+b315bd0c19f44409f9dec5677c30dec657327e46df81c249ddbd509e0ba541c2

python/tests/golden/aether_input.json

@@ -0,0 +1 @@
+[[0.0, 0.00390625, 0.0078125, 0.01171875, 0.015625, 0.01953125, 0.0234375, 0.02734375, 0.03125, 0.03515625, 0.0390625, 0.04296875, 0.046875, 0.05078125, 0.0546875, 0.05859375, 0.0625, 0.06640625, 0.0703125, 0.07421875, 0.078125, 0.08203125, 0.0859375, 0.08984375, 0.09375, 0.09765625, 0.1015625, 0.10546875, 0.109375, 0.11328125, 0.1171875, 0.12109375, 0.125, 0.12890625, 0.1328125, 0.13671875, 0.140625, 0.14453125, 0.1484375, 0.15234375, 0.15625, 0.16015625, 0.1640625, 0.16796875, 0.171875, 0.17578125, 0.1796875, 0.18359375, 0.1875, 0.19140625, 0.1953125, 0.19921875, 0.203125, 0.20703125, 0.2109375, 0.21484375], [0.21875, 0.22265625, 0.2265625, 0.23046875, 0.234375, 0.23828125, 0.2421875, 0.24609375, 0.25, 0.25390625, 0.2578125, 0.26171875, 0.265625, 0.26953125, 0.2734375, 0.27734375, 0.28125, 0.28515625, 0.2890625, 0.29296875, 0.296875, 0.30078125, 0.3046875, 0.30859375, 0.3125, 0.31640625, 0.3203125, 0.32421875, 0.328125, 0.33203125, 0.3359375, 0.33984375, 0.34375, 0.34765625, 0.3515625, 0.35546875, 0.359375, 0.36328125, 0.3671875, 0.37109375, 0.375, 0.37890625, 0.3828125, 0.38671875, 0.390625, 0.39453125, 0.3984375, 0.40234375, 0.40625, 0.41015625, 0.4140625, 0.41796875, 0.421875, 0.42578125, 0.4296875, 0.43359375], [0.4375, 0.44140625, 0.4453125, 0.44921875, 0.453125, 0.45703125, 0.4609375, 0.46484375, 0.46875, 0.47265625, 0.4765625, 0.48046875, 0.484375, 0.48828125, 0.4921875, 0.49609375, 0.5, 0.50390625, 0.5078125, 0.51171875, 0.515625, 0.51953125, 0.5234375, 0.52734375, 0.53125, 0.53515625, 0.5390625, 0.54296875, 0.546875, 0.55078125, 0.5546875, 0.55859375, 0.5625, 0.56640625, 0.5703125, 0.57421875, 0.578125, 0.58203125, 0.5859375, 0.58984375, 0.59375, 0.59765625, 0.6015625, 0.60546875, 0.609375, 0.61328125, 0.6171875, 0.62109375, 0.625, 0.62890625, 0.6328125, 0.63671875, 0.640625, 0.64453125, 0.6484375, 0.65234375], [0.65625, 0.66015625, 0.6640625, 0.66796875, 0.671875, 0.67578125, 0.6796875, 0.68359375, 0.6875, 0.69140625, 0.6953125, 0.69921875, 0.703125, 0.70703125, 0.7109375, 0.71484375, 0.71875, 0.72265625, 0.7265625, 0.73046875, 0.734375, 0.73828125, 0.7421875, 0.74609375, 0.75, 0.75390625, 0.7578125, 0.76171875, 0.765625, 0.76953125, 0.7734375, 0.77734375, 0.78125, 0.78515625, 0.7890625, 0.79296875, 0.796875, 0.80078125, 0.8046875, 0.80859375, 0.8125, 0.81640625, 0.8203125, 0.82421875, 0.828125, 0.83203125, 0.8359375, 0.83984375, 0.84375, 0.84765625, 0.8515625, 0.85546875, 0.859375, 0.86328125, 0.8671875, 0.87109375], [0.875, 0.87890625, 0.8828125, 0.88671875, 0.890625, 0.89453125, 0.8984375, 0.90234375, 0.90625, 0.91015625, 0.9140625, 0.91796875, 0.921875, 0.92578125, 0.9296875, 0.93359375, 0.9375, 0.94140625, 0.9453125, 0.94921875, 0.953125, 0.95703125, 0.9609375, 0.96484375, 0.96875, 0.97265625, 0.9765625, 0.98046875, 0.984375, 0.98828125, 0.9921875, 0.99609375, 0.0, 0.00390625, 0.0078125, 0.01171875, 0.015625, 0.01953125, 0.0234375, 0.02734375, 0.03125, 0.03515625, 0.0390625, 0.04296875, 0.046875, 0.05078125, 0.0546875, 0.05859375, 0.0625, 0.06640625, 0.0703125, 0.07421875, 0.078125, 0.08203125, 0.0859375, 0.08984375], [0.09375, 0.09765625, 0.1015625, 0.10546875, 0.109375, 0.11328125, 0.1171875, 0.12109375, 0.125, 0.12890625, 0.1328125, 0.13671875, 0.140625, 0.14453125, 0.1484375, 0.15234375, 0.15625, 0.16015625, 0.1640625, 0.16796875, 0.171875, 0.17578125, 0.1796875, 0.18359375, 0.1875, 0.19140625, 0.1953125, 0.19921875, 0.203125, 0.20703125, 0.2109375, 0.21484375, 0.21875, 0.22265625, 0.2265625, 0.23046875, 0.234375, 0.23828125, 0.2421875, 0.24609375, 0.25, 0.25390625, 0.2578125, 0.26171875, 0.265625, 0.26953125, 0.2734375, 0.27734375, 0.28125, 0.28515625, 0.2890625, 0.29296875, 0.296875, 0.30078125, 0.3046875, 0.30859375], [0.3125, 0.31640625, 0.3203125, 0.32421875, 0.328125, 0.33203125, 0.3359375, 0.33984375, 0.34375, 0.34765625, 0.3515625, 0.35546875, 0.359375, 0.36328125, 0.3671875, 0.37109375, 0.375, 0.37890625, 0.3828125, 0.38671875, 0.390625, 0.39453125, 0.3984375, 0.40234375, 0.40625, 0.41015625, 0.4140625, 0.41796875, 0.421875, 0.42578125, 0.4296875, 0.43359375, 0.4375, 0.44140625, 0.4453125, 0.44921875, 0.453125, 0.45703125, 0.4609375, 0.46484375, 0.46875, 0.47265625, 0.4765625, 0.48046875, 0.484375, 0.48828125, 0.4921875, 0.49609375, 0.5, 0.50390625, 0.5078125, 0.51171875, 0.515625, 0.51953125, 0.5234375, 0.52734375], [0.53125, 0.53515625, 0.5390625, 0.54296875, 0.546875, 0.55078125, 0.5546875, 0.55859375, 0.5625, 0.56640625, 0.5703125, 0.57421875, 0.578125, 0.58203125, 0.5859375, 0.58984375, 0.59375, 0.59765625, 0.6015625, 0.60546875, 0.609375, 0.61328125, 0.6171875, 0.62109375, 0.625, 0.62890625, 0.6328125, 0.63671875, 0.640625, 0.64453125, 0.6484375, 0.65234375, 0.65625, 0.66015625, 0.6640625, 0.66796875, 0.671875, 0.67578125, 0.6796875, 0.68359375, 0.6875, 0.69140625, 0.6953125, 0.69921875, 0.703125, 0.70703125, 0.7109375, 0.71484375, 0.71875, 0.72265625, 0.7265625, 0.73046875, 0.734375, 0.73828125, 0.7421875, 0.74609375]]

python/tests/test_aether.py

@@ -0,0 +1,103 @@
+"""ADR-185 P1 — AETHER binding tests, incl. the §4.1 bit-for-bit parity gate.
+
+The parity test packs the binding's embedding to little-endian f32 bytes
+and asserts its SHA-256 equals the committed golden produced by the
+native-Rust reference (`tests/aether_parity.rs`). A mismatch is a
+release blocker, not a warning.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import math
+import struct
+from pathlib import Path
+
+import pytest
+
+from wifi_densepose import aether
+
+GOLDEN = Path(__file__).parent / "golden"
+
+
+def load_input() -> list[list[float]]:
+    return json.loads((GOLDEN / "aether_input.json").read_text())
+
+
+def build_extractor() -> aether.EmbeddingExtractor:
+    # Must match the native-Rust reference construction exactly.
+    cfg = aether.AetherConfig(d_model=64, d_proj=128, temperature=0.07, normalize=True)
+    return aether.EmbeddingExtractor(n_subcarriers=56, config=cfg)
+
+
+def test_config_roundtrips_fields() -> None:
+    cfg = aether.AetherConfig(d_model=64, d_proj=128, temperature=0.07, normalize=True)
+    assert cfg.d_model == 64
+    assert cfg.d_proj == 128
+    assert abs(cfg.temperature - 0.07) < 1e-6
+    assert cfg.normalize is True
+
+
+def test_embedding_shape_and_unit_norm() -> None:
+    emb = build_extractor().embed(load_input())
+    assert len(emb) == 128
+    norm = math.sqrt(sum(x * x for x in emb))
+    assert abs(norm - 1.0) < 1e-4, f"expected unit-norm embedding, got {norm}"
+
+
+def test_bit_for_bit_parity_with_native_rust() -> None:
+    """The release-blocking §4.1 gate: binding output == native Rust, byte-for-byte."""
+    emb = build_extractor().embed(load_input())
+    packed = b"".join(struct.pack("<f", x) for x in emb)
+    got = hashlib.sha256(packed).hexdigest()
+    expected = (GOLDEN / "aether_embedding.sha256").read_text().strip()
+    assert got == expected, (
+        "Python binding embedding diverged from the native-Rust golden "
+        f"({got} != {expected}) — PyO3 marshalling is not byte-identical."
+    )
+
+
+def test_embedding_is_deterministic() -> None:
+    ext = build_extractor()
+    inp = load_input()
+    assert ext.embed(inp) == ext.embed(inp)
+
+
+def test_cosine_similarity_self_is_one() -> None:
+    v = [0.1 * i - 0.5 for i in range(32)]
+    assert abs(aether.cosine_similarity(v, v) - 1.0) < 1e-5
+
+
+def test_cosine_similarity_orthogonal_is_zero() -> None:
+    a = [1.0, 0.0, 0.0, 0.0]
+    b = [0.0, 1.0, 0.0, 0.0]
+    assert abs(aether.cosine_similarity(a, b)) < 1e-6
+
+
+def test_info_nce_loss_identical_batch_is_log_n() -> None:
+    # Identical embeddings → all similarities equal → loss == ln(N).
+    emb = [[1.0, 0.0, 0.0]] * 4
+    loss = aether.info_nce_loss(emb, emb, 0.07)
+    assert abs(loss - math.log(4)) < 0.1
+
+
+def test_augment_pair_preserves_shape_and_differs() -> None:
+    window = load_input()
+    view_a, view_b = aether.CsiAugmenter().augment_pair(window, seed=42)
+    assert len(view_a) == len(window)
+    assert len(view_b) == len(window)
+    assert len(view_a[0]) == len(window[0])
+    differs = any(
+        abs(x - y) > 1e-6
+        for ra, rb in zip(view_a, view_b)
+        for x, y in zip(ra, rb)
+    )
+    assert differs, "augment_pair should return two distinct views"
+
+
+def test_base_wheel_import_error_message() -> None:
+    # This wheel HAS the extra, so the import succeeds; assert the guard
+    # message is present in source so the base-wheel path stays honest.
+    src = (Path(aether.__file__)).read_text()
+    assert "pip install wifi-densepose[aether]" in src