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/Cargo.toml

@@ -23,6 +23,15 @@ name = "wifi_densepose_native"
 crate-type = ["cdylib", "rlib"]
 path = "src/lib.rs"
 
+# ADR-185 §3.1 — optional pip extras map to Cargo features so the
+# default wheel links none of the SOTA subsystems. P1 wires `aether`.
+[features]
+default = []
+# ADR-185 P1 — AETHER contrastive CSI embeddings. Pulls the backing
+# `wifi-densepose-sensing-server` crate (see the honest wheel-size note
+# on that dep below).
+aether = ["dep:wifi-densepose-sensing-server"]
+
 [dependencies]
 # PyO3 with abi3-py310 — one compiled binary covers Python 3.10, 3.11,
 # 3.12, 3.13, and any future 3.x that keeps the stable ABI (ADR-117 §5.4).
@@ -50,6 +59,24 @@ wifi-densepose-bfld = { version = "0.3.0", path = "../v2/crates/wifi-densepose-b
 # the future P3 CsiFrame numpy round-trip.
 numpy = "0.22"
 
+# ADR-185 P1 — AETHER backing crate (contrastive `embedding` module,
+# ADR-024). Optional + gated behind the `aether` feature.
+#
+# HONEST WHEEL-SIZE NOTE (ADR-185 §9 / Open Q §11.1): this crate is an
+# Axum/tokio server crate. `default-features = false` does NOT drop
+# tokio/axum here — they are non-optional deps (only `mqtt`/`matter`
+# are features). So an `[aether]` wheel currently links the full
+# sensing-server dependency tree, breaking the ADR-117 §5.4 ≤5 MB
+# budget. The ADR-sanctioned fix is to hoist `embedding.rs` (+ its
+# `graph_transformer`/`sona` siblings) into a leaf crate so the wheel
+# links only pure compute — a Rust-side refactor inside
+# `wifi-densepose-sensing-server`, owned by another agent this session.
+# P1 binds against the real code and proves parity; the leaf-crate
+# hoist is the required pre-release follow-up.
+wifi-densepose-sensing-server = { version = "0.3.0", path = "../v2/crates/wifi-densepose-sensing-server", optional = true, default-features = false }
+
 [dev-dependencies]
-# Doc-test infrastructure for the Python-facing examples in the bound
-# Rust functions. Lands properly in P2 once #[pyfunction]s exist to test.
+# ADR-185 §4.1 parity harness — SHA-256 the native-Rust reference
+# embedding and read the committed golden fixture.
+sha2 = "0.10"
+serde_json = "1"