Update missing drug concept UUIDs in drugs-core_demo.csv (#56)
Replace broken concept UUID references with valid concept UUIDs from
drugs_concepts-core_demo.csv to prevent initialization errors.
Updated drugs:
- Augmentin 600mg+42.9mg/75ml: use Amoxicillin & Clavulanate concept
- Bactoclav 500mg+125mg: use Amoxicillin & Clavulanate concept
- Gentamicin 0.3%: use Gentamicin concept
- Inderal 80mg: use Propranolol hydrochloride concept
The original UUIDs were orphaned references that didn't exist in any
concepts file, causing drug initialization to fail.
