This update cleans up older email-related code and prepares the mail system for future speed improvements. It should have little direct impact on day-to-day users, but helps make email handling more reliable and easier to improve over time.

This update tidies the internal stock picking completion process and ensures it is used through the standard validation flow. It helps reduce maintenance risk across inventory, manufacturing, purchasing, sales, delivery, and point of sale operations without changing day-to-day user behavior.

This change restructures how stock transfers are marked as done, making that process internal to reduce unintended use by related apps. It helps keep delivery, marketplace, helpdesk, field service, and quality workflows aligned while preserving expected behavior through updated tests.