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/crates/rvcsi-cli/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "rvcsi-cli"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+description = "rvCSI command-line tool — inspect, replay, stream, calibrate, health, export (ADR-095 FR7)"
+repository.workspace = true
+keywords = ["wifi", "csi", "cli", "rvcsi"]
+categories = ["science", "command-line-utilities"]
+
+[[bin]]
+name = "rvcsi"
+path = "src/main.rs"
+
+[dependencies]
+rvcsi-core = { path = "../rvcsi-core" }
+rvcsi-dsp = { path = "../rvcsi-dsp" }
+rvcsi-events = { path = "../rvcsi-events" }
+rvcsi-adapter-file = { path = "../rvcsi-adapter-file" }
+rvcsi-adapter-nexmon = { path = "../rvcsi-adapter-nexmon" }
+rvcsi-ruvector = { path = "../rvcsi-ruvector" }
+clap = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+anyhow = { workspace = true }