feat(homecore-recorder/p2): wire RuvectorSemanticIndex with hash-based embeddings (resolves ADR-132 P2)
- ruvector-core = "2.2.0" + sha2 = "0.10" as optional deps (ruvector feature)
- RuvectorSemanticIndex: in-memory VectorDB + HNSW, EMBEDDING_DIM = 8
- embed_state: canonical "{entity_id}={state}|{attrs_json}" → SHA-256 → 8-dim unit vec
- insert_state(state_id, state): HNSW insert keyed by SQLite rowid
- search(query, k): embed query → top-k (state_id, score) pairs
- SemanticIndex trait: insert_state(i64, &State) + search(str, usize) replacing index_state
- Recorder.semantic: Arc<RwLock<dyn SemanticIndex>> for interior mutability
- Recorder::search_semantic(query, k): HNSW → SQLite JOIN → Vec<StateRow>
- Tests: 20 passed (was 14 at P1): determinism, unit-norm, dim, insert+search, ranking, e2e
- P3 note: swap embed_bytes for ruvector-attention; raise dim to 384
Co-Authored-By: claude-flow <ruv@ruv.net>
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