v3.2.20

feat: 8 arch improvements + shattering tests; bump 3.2.20

- SemanticCache: /api/cache/stats endpoint + 2 new tests
- KnowledgeGraph: extract_and_store() auto-populates KG from conversations
- VocabPruner (node/): adaptive vocabulary pruning 151936->2000 tokens on lm_head
- ThoughtCache: memoized reasoning chains, TF-IDF threshold=0.88, TTL=3d
- ComplexityScorer + ITCS: fast/normal/deep pipeline budget per query
- MemoryCompressor: semantic clustering of episodic memory
- FactualValidator: cross-checks responses against KG
- IntentPredictor + CacheWarmer: predicts follow-ups, pre-warms cache
- Shattering: 7/7 end-to-end tests pass; GitHub Actions CI workflow added

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>