fix: drop+recreate DB schema on startup to clear old v1 tables

backend/start.sh

@@ -4,11 +4,22 @@ set -e
 echo "Waiting for database..."
 sleep 3
 
-echo "Running migrations..."
-python -c "from app.database import engine; from app.models import Base; Base.metadata.create_all(bind=engine)"
+echo "Resetting database schema..."
+python -c "
+from app.database import engine
+from app.models import Base
+import sqlalchemy as sa
+
+# Drop all tables for clean v2 schema
+print('Dropping old tables...')
+Base.metadata.drop_all(bind=engine)
+print('Creating new tables...')
+Base.metadata.create_all(bind=engine)
+print('Schema ready.')
+"
 
 echo "Seeding data..."
-python /app/seed.py || echo "Seed already exists or failed (non-fatal)"
+python /app/seed.py
 
 echo "Starting server..."
 exec uvicorn app.main:app --host 0.0.0.0 --port 8000 --workers 1