Replace cursor.copy() with cursor.executemany() for more reliable
batch inserts in PostgreSQL. The COPY method has issues with format
and data encoding in psycopg3.
Changes:
- Use executemany() with parameterized INSERT statements
- Let psycopg handle parameter escaping and encoding
- Convert JSONB dicts to JSON strings automatically
- More compatible with various data types
This ensures that data is actually being inserted into PostgreSQL
during migration, fixing the issue where data wasn't appearing in
the database after migration completed.
Fixes: Data not being persisted in PostgreSQL during migration
alex
821cda850e