feat(terraphim_types): add knowledge graph normalization example

Example that:
- Loads markdown files from a knowledge corpus
- Builds ontology/thesaurus from linked_terms and headers
- Extracts and normalizes entities with confidence scores
- Computes coverage signals to judge quality
- Exports thesaurus for Terraphim automata

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

Author: Terraphim CI