Phase 6.2+6.3: Add Fisher-Backends and EWC-Integration wiki pages; update sidebar - Phase-6-Fisher-Backends.md: Neo4jFisherStore (schema, skeleton, latency table), CachedFisherStore (Redis TTL cache, Prometheus counters, key convention), FisherStoreFactory (match pattern, registry), 12 test targets, error handling - Phase-6-EWC-Integration.md: penalty_gradient() method, _apply_ewc_constraint(), modified update() signature, 4 new Prometheus metrics, 10 test targets, implementation order, interaction with Phase 5 components - _Sidebar.md: Phase 6 section expanded with Fisher Backends + EWC Integration links Closes #245 (Fisher backends wiki coverage) Refs #249 (EWC integration issue)