feat(ontology): add specialized agents and HGNC gene normalization

Complete Dynamic Ontology implementation with:
- Specialized agents (Extraction, Normalization, Coverage, Review)
- HGNC gene normalization module with 20+ oncology genes
- Integration tests for the full pipeline

Files:
- ontology_agents.rs: Specialized agent structs
- hgnc.rs: Gene normalizer with exact + fuzzy matching
- ontology_integration_test.rs: 8 integration tests

Uses existing fuzzy matching (Levenshtein/Jaro-Winkler) and graph
ranking - no vector embeddings needed.

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

Author: Terraphim CI

crates/terraphim_multi_agent/src/agents/mod.rs

@@ -4,9 +4,11 @@
 //! to provide specific functionality like summarization, chat, and other domain-specific tasks.
 
 pub mod chat_agent;
+pub mod ontology_agents;
 pub mod summarization_agent;
 
 pub use chat_agent::*;
+pub use ontology_agents::*;
 pub use summarization_agent::*;
 
 // Re-export commonly used types