feat(ruvector): ADR-084 Pass 1 — sketch module foundation

Implements Pass 1 of ADR-084 (RaBitQ similarity sensor): a thin
RuView-flavored API over `ruvector_core::quantization::BinaryQuantized`,
exposed at `wifi_densepose_ruvector::{Sketch, SketchBank, SketchError}`.

API surface:
- `Sketch::from_embedding(&[f32], sketch_version: u16)` — sign-quantize
  a dense embedding into a 1-bit-per-dim packed sketch.
- `Sketch::distance` — hamming distance with schema-mismatch error.
- `Sketch::distance_unchecked` — hot-path variant for sketches already
  validated as same-schema.
- `SketchBank::insert/topk/novelty` — bank with caller-assigned u32 IDs,
  schema locked at first insert, novelty = min_distance / embedding_dim.

Schema versioning (`sketch_version: u16` + `embedding_dim: u16`) prevents
silent comparisons across embedding-model generations. Bumping the model
forces re-sketch of the candidate bank.

Pass 1 establishes the API and unit-test foundation. Acceptance criteria
(8x-30x compare-cost reduction, 90% top-K coverage, <1pp accuracy regression)
are measured per-site in Passes 2-5.

Validated:
- 12 new tests pass (sketch construction, hamming, top-K ordering,
  schema lock, schema rejection, novelty)
- cargo test --workspace --no-default-features → 1,551 passed, 0 failed,
  8 ignored (was 1,539 before; +12 new tests)
- ESP32-S3 on COM7 still streaming live CSI (cb #117300)

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

v2/Cargo.toml

@@ -120,6 +120,7 @@ midstreamer-attractor = "0.1.0"
 
 # ruvector integration (published on crates.io)
 # Vendored at v2.1.0 in vendor/ruvector; using crates.io versions until published.
+ruvector-core = "2.0.4"
 ruvector-mincut = "2.0.4"
 ruvector-attn-mincut = "2.0.4"
 ruvector-temporal-tensor = "2.0.4"