feat(wifi-densepose-sar): coherent wideband RF tomography research crate (ADR-283)

New standalone leaf crate implementing the synthetic-aperture-radar
reconstruction primitive a handheld through-wall RF imaging device
would need: a stepped-frequency multi-position complex forward
measurement simulator, delay-and-sum backprojection reconstruction,
point-cloud extraction, and closed-form range/cross-range resolution
+ antenna-pose coherence-budget formulas checked against the
reconstruction's actual behavior in tests/physics_validation.rs.

Motivated by comparing this repo against Applied Electrodynamics'
"WaveSight" launch. Scoped explicitly below ADR-278's RISE/DiffRadar/
GeRaF reproduction gates: this is the bare measurement-model +
backprojection primitive, not a reproduction of any published system
or a claim about real hardware capability. Every number is
SYNTHETIC/L0 (ADR-282) -- no wideband RF hardware backs this crate.

24 tests (21 unit + 3 integration), 0 failed, clippy-clean. Adds a
tutorial walkthrough and MEASURED backprojection benchmark numbers.

v2/Cargo.toml

@@ -88,6 +88,12 @@ members = [
     # submodule crates (rufield-core/-provenance/-privacy/-fusion); single
     # coupling point between RuView and the standalone RuField MFS spec.
     "crates/wifi-densepose-rufield",
+    # ADR-283 — coherent wideband RF tomography research crate: synthetic
+    # stepped-frequency multi-position measurement simulation + delay-and-sum
+    # backprojection reconstruction. Standalone leaf (nvsim pattern), zero
+    # hardware coupling, every number SYNTHETIC/L0 until real wideband RF
+    # hardware exists.
+    "crates/wifi-densepose-sar",
 ]
 # ADR-040: WASM edge crate targets wasm32-unknown-unknown (no_std),
 # excluded from workspace to avoid breaking `cargo test --workspace`.