Replace the logging-only stub in logic_gameplay.py with the real
notify_tier_completion from helpers/refractor_notifs.py. Tier-up
events now send Discord embeds instead of just logging.
- Import notify_tier_completion from helpers.refractor_notifs
- Remove 16-line stub function and redundant inline logging
- Update tests: verify real embed-sending behavior, replace
bug-documenting T1-5 diagnostic with shape validation guards
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>