v0.4: optional embedding expert for real semantic similarity. New projection.py (dense->HV via random projection + sign, cosine-preserving). EmbeddingExpert plugs into the brain unchanged (duck-typed Expert contract) and makes spain~portugal similar at the HV level (the missing ingredient for analogy). Two paths: from_corpus_local (PPMI+SVD mini-embedding, numpy-only) and from_fasttext (pretrained .vec). StructuralEncoder.attach_embedding wires semantic slot HVs. Honest: mini-embedding brings semantic similarity (measurable) but factual correctness stays ~0% (needs fastText + better decoding); pipeline ready. 106 tests.