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

python/wifi_densepose/mat.py

@@ -3,9 +3,10 @@
 WiFi-based disaster-survivor detection and START-protocol triage from CSI:
 ingest CSI frames, run a scan cycle, and query detected survivors by triage.
 
-Included in the official ``wifi-densepose`` wheels. It is absent only from a
-from-source build that did not enable the Rust ``mat`` feature; rebuild with
-``maturin ... --features mat`` (or ``--features sota``) in that case.
+Not in the binary wheels yet (see ruvnet/RuView#1412 — the P6 SOTA
+bindings are shipped source-build-only for now to keep the base wheel
+small). Build from source with ``maturin ... --features mat`` (or
+``--features sota`` for all three P6 subsystems).
 
 Quick start::
 
@@ -36,8 +37,8 @@ from wifi_densepose import _native
 # MAT symbols are compiled into `_native` only under the Rust `mat` feature.
 if not hasattr(_native, "DisasterResponse"):
     raise ImportError(
-        "wifi_densepose.mat is not available in this build. The official "
-        "wheels include it; if you built from source, rebuild with "
+        "wifi_densepose.mat is not in the binary wheels yet "
+        "(see ruvnet/RuView#1412). Build from source with "
         "`maturin ... --features mat` (or `--features sota`)."
     )