feat(rvcsi): rvcsi-core + napi-c Nexmon shim + crate skeletons (ADR-095/096)

First implementation milestone for the rvCSI edge RF sensing runtime:

- rvcsi-core — the foundation: CsiFrame/CsiWindow/CsiEvent normalized schema,
  ValidationStatus, AdapterProfile, CsiSource plugin trait, id newtypes +
  IdGenerator, RvcsiError, and the validate_frame pipeline (length/finiteness/
  subcarrier/RSSI/monotonicity hard checks + multiplicative quality scoring →
  Accepted/Degraded/Recovered/Rejected). 29 unit tests, forbid(unsafe_code).
- rvcsi-adapter-nexmon — the napi-c boundary: native/rvcsi_nexmon_shim.{c,h}
  (the only C in the runtime, allocation-free, bounds-checked, parses/writes a
  byte-defined "rvCSI Nexmon record" — a normalized superset of the nexmon_csi
  UDP payload), compiled via build.rs + cc, wrapped by a documented ffi module
  and a NexmonAdapter implementing CsiSource. 9 tests round-tripping through C.
- Workspace registration in v2/Cargo.toml (8 new members + napi/cc workspace
  deps) and compiling skeletons for rvcsi-dsp, rvcsi-events, rvcsi-adapter-file,
  rvcsi-ruvector, rvcsi-node (napi-rs cdylib + build.rs napi_build::setup) and
  rvcsi-cli (`rvcsi` binary) — to be filled in by the implementation swarm.

cargo build -p rvcsi-core -p rvcsi-adapter-nexmon -p rvcsi-node -p rvcsi-cli: OK
cargo test  -p rvcsi-core -p rvcsi-adapter-nexmon: 38 passed, 0 failed

https://claude.ai/code/session_01CdYAPvRTjcch6YrYf42n1z

v2/Cargo.toml

@@ -21,6 +21,15 @@ members = [
     "crates/wifi-densepose-geo",
     "crates/nvsim",
     "crates/nvsim-server",
+    # rvCSI — edge RF sensing runtime (ADR-095 platform, ADR-096 FFI/crate layout)
+    "crates/rvcsi-core",
+    "crates/rvcsi-dsp",
+    "crates/rvcsi-events",
+    "crates/rvcsi-adapter-file",
+    "crates/rvcsi-adapter-nexmon",
+    "crates/rvcsi-ruvector",
+    "crates/rvcsi-node",
+    "crates/rvcsi-cli",
 ]
 # ADR-040: WASM edge crate targets wasm32-unknown-unknown (no_std),
 # excluded from workspace to avoid breaking `cargo test --workspace`.
@@ -108,6 +117,13 @@ indicatif = "0.17"
 # CLI
 clap = { version = "4.4", features = ["derive", "env"] }
 
+# rvCSI: napi-rs (Rust -> Node bindings) + napi-c (C-shim build glue)
+napi = { version = "2.16", default-features = false, features = ["napi8"] }
+napi-derive = "2.16"
+napi-build = "2.1"
+cc = "1.0"
+libc = "0.2"
+
 # Testing
 criterion = { version = "0.5", features = ["html_reports"] }
 proptest = "1.4"