feat(adr-117/p3+p3.5): vitals + BFLD bindings

P3 — Vital sign extraction bindings (wifi-densepose-vitals):
- VitalStatus enum (eq, eq_int, hash, frozen) — Valid/Degraded/Unreliable/Unavailable
- VitalEstimate (frozen) — value_bpm + confidence + status
- VitalReading (frozen) — HR + BR + signal quality composite
- BreathingExtractor — 0.1–0.5 Hz bandpass + zero-crossing
- HeartRateExtractor — 0.8–2.0 Hz bandpass + autocorrelation
- py.allow_threads on extract() hot loops (Q5 audit confirmed
  core/vitals/signal are pure-sync — zero tokio deps, safe to release
  GIL with no embedded runtime needed)
- 17 tests covering construction, getters, frozen immutability,
  esp32_default + explicit ctors, synthetic-signal end-to-end

P3.5 — BFLD bindings (forward-compat surface, stub Rust):
- BfldKind enum — CompressedHE20/40/80/160 + UncompressedHT20/40
  with n_subcarriers, bandwidth_mhz, is_he metadata getters
- BfldFrame (frozen) — from_compressed_feedback() accepts numpy
  Complex64 ndarray [Nr x Nc x Nsc], validates dims against kind,
  feedback_matrix() returns lossless roundtrip ndarray
- BfldReport — aggregates frames, rejects mismatched kinds,
  computes inverse-CV coherence score
- 19 tests covering all 6 PHY variants + numpy roundtrip +
  dim-mismatch error + aggregation
- Real Rust ingestion (wifi-densepose-bfld crate) lands post-v2.0
  per ADR-117 §11.11/12 — Python API will not change

Total Python test count: 93 (was 57, +36 P3+P3.5). All passing.

Refs: docs/adr/ADR-117-pip-wifi-densepose-modernization.md
Refs: #785

Co-Authored-By: claude-flow <ruv@ruv.net>

python/Cargo.toml

@@ -35,6 +35,14 @@ pyo3 = { version = "0.22", features = ["extension-module", "abi3-py310"] }
 # budget by avoiding optional BLAS/openssl chains.
 wifi-densepose-core = { version = "0.3.0", path = "../v2/crates/wifi-densepose-core" }
 
+# P3 — vitals extraction (HR/BR via the 4-stage pipeline). Pure-sync;
+# no tokio (Q5 audited 2026-05-24); safe to wrap in py.allow_threads.
+wifi-densepose-vitals = { version = "0.3.0", path = "../v2/crates/wifi-densepose-vitals" }
+
+# numpy bridge — needed for P3.5 BfldFrame (Complex64 ndarray) and for
+# the future P3 CsiFrame numpy round-trip.
+numpy = "0.22"
+
 [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.