Rename mimic_omop example to omop-mssql

Consolidate the OMOP example under examples/omop-mssql. The mimic_omop
orm.yaml becomes orm_full.yaml; a trimmed orm.yaml and a
copy_vocabulary.sql helper script are added alongside it.

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

Author: myyong