meeting-assistant/openspec/changes/archive/2026-05-20-add-teams-scheduled-end-context/tasks.md

1. Scheduled End Metadata

• 1.1 Extend Teams meeting metadata with scheduled end time.
• 1.2 Write scheduled_end to assistant context frontmatter only when Teams metadata is detected.
• 1.3 Preserve scheduled_end across assistant context state updates.
• 1.4 Add behavior tests and validate the OpenSpec change.