revert(python): keep the small base wheel — P6 stays source-build-only for now

Reverses the release-wheel packaging change from 3ed43e9a after review.

That commit built the published wheels with `--features sota` so
`pip install wifi-densepose[aether]` would work. But it did so by abandoning a
DELIBERATE, guarded design: `default = []`, the
RuView#1387-default-wheel-budget-config fix-marker, and the wheel-size-budget
job exist specifically to keep the base wheel small and make SOTA opt-in
(ADR-117 §5.4). Building SOTA into every published wheel makes the base fat,
turns the `[aether]`/`[mat]`/`[meridian]` extras into inert no-ops, and — worse
— leaves the PUBLISHED wheel un-budget-checked (the budget job only builds the
no-features wheel), so the ONNX Runtime dependency the fix-marker anticipates
for `mat` would later balloon the shipped wheel past 5 MiB silently.

A pip extra cannot enable a cargo feature on a prebuilt wheel, so "small base +
opt-in SOTA in binary wheels" is only achievable by splitting into separate
packages — tracked as #1412. Until that lands, P6 is source-build-only, and the
honest thing is to say so.

This commit:
- Restores pip-release.yml to its original state (no --features in the release
  build; original smoke test). Net packaging change across the branch is now
  ZERO — the small-base design is fully intact.
- Points the aether/mat/meridian import shims at the real interim path: a source
  build with `--features <x>` (or `--features sota`), and #1412 for the binary
  wheels follow-up. The earlier revision wrongly claimed "the official wheels
  include it", which is only true once #1412 ships.

KEPT from 3ed43e9a (correct regardless of packaging): the AETHER parity tests
are now arch-portable — they compare a golden VECTOR within tolerance instead of
a SHA-256 of raw f32 bytes, which only ever matched the one architecture that
generated it and failed on the aarch64/macOS-arm wheels this project builds.

Verified on aarch64/macOS with a `--features sota` build (as python-ci does):
test_aether 13, test_mat 7, test_meridian 13 pass; full suite unaffected.

Co-Authored-By: Ruflo & AQE

.github/workflows/pip-release.yml

@@ -111,33 +111,16 @@ jobs:
           CIBW_ARCHS_WINDOWS: ${{ matrix.arch }}
           CIBW_BUILD_FRONTEND: "build"
           CIBW_BEFORE_BUILD: "pip install maturin>=1.7"
-          # PUBLISHED wheels carry the full SOTA feature set. A pip extra
-          # (`[aether]`) CANNOT enable a Rust cargo feature on an already-built
-          # wheel, so the only way P6 reaches PyPI users is to compile it in.
-          # `default = []` stays in Cargo.toml (dev builds + the wheel-size
-          # budget job keep guarding the small base compile); the RELEASE build
-          # opts in here via maturin's PEP517 args. Measured 1.68 MiB — well
-          # under the ADR-117 §5.4 5 MiB budget. Set per-platform because
-          # CIBW_ENVIRONMENT_LINUX overrides the general CIBW_ENVIRONMENT.
-          CIBW_ENVIRONMENT: 'MATURIN_PEP517_ARGS="--features sota"'
           # The PyO3 sdist landing depends on the cargo/Rust toolchain
           # being present. cibuildwheel images carry rustup on Linux
           # but we also pin a known-good version for reproducibility.
           CIBW_BEFORE_ALL_LINUX: "curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.82"
-          CIBW_ENVIRONMENT_LINUX: 'PATH="$HOME/.cargo/bin:$PATH" MATURIN_PEP517_ARGS="--features sota"'
-          # Smoke-test every built wheel before accepting it. This ASSERTS the
-          # SOTA bindings are present and importable — the prior version only
-          # printed __build_features__ and asserted hello(), so a wheel missing
-          # every P6 binding published green. A featureless wheel now fails here
-          # instead of shipping an ImportError to users.
+          CIBW_ENVIRONMENT_LINUX: 'PATH="$HOME/.cargo/bin:$PATH"'
+          # Smoke-test every built wheel before accepting it. Catches
+          # the case where the wheel imports but the compiled symbols
+          # are missing.
           CIBW_TEST_REQUIRES: "pytest>=8.0"
-          CIBW_TEST_COMMAND: >-
-            python -c "import wifi_densepose as w;
-            assert w.hello() == 'ok';
-            missing = [f for f in ('p6-aether-bindings','p6-meridian-bindings','p6-mat-bindings') if f not in w.__build_features__];
-            assert not missing, ('published wheel is missing SOTA bindings: ' + str(missing) + ' have=' + str(w.__build_features__));
-            import wifi_densepose.aether, wifi_densepose.mat, wifi_densepose.meridian;
-            print('OK — SOTA bindings present:', w.__build_features__)"
+          CIBW_TEST_COMMAND: 'python -c "import wifi_densepose; assert wifi_densepose.hello() == \"ok\"; print(wifi_densepose.__build_features__)"'
         with:
           package-dir: python
           output-dir: wheelhouse