Force ntn to authenticate as the same integration that writes the page by
injecting NOTION_API_TOKEN=$NOTION_API_KEY into every ntn subprocess env.
Notion scopes file uploads to the creating integration, so a mismatch caused
"Could not find file_upload with ID …" when attaching uploaded images.
Added test_upload_passes_token_env (9 total in test_ntn_files.py) and updated
code/CLAUDE.md to reflect that a separate ntn login is no longer required.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
