Harden retrain merge and OPC write against silent failures
- pandas merge now uses validate='one_to_one' so duplicated timestamps
from wrapper.retrain fail loudly instead of silently multiplying rows
- OPC write_data raises OpcClientNotInitializedError instead of a bare
assert when client is torn down between validation and write, so
callers get a reported error instead of an AssertionError
- add regression test covering the torn-down client path
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
vitor-aignosi
f323da7b56