sync-pr-to-notion

Use when asked to sync a branch's changes into its linked Notion card, or to update the Notion ticket for a PR. Looks up the card from the PR record written by manage-pr (keyed by project and branch), asks the user for the card if none is recorded, then writes a high-level architecture-style description of the branch's changes to the card via the write-notion-content skill. Never edits code, tests, or verification steps. Triggers on "sync the PR to notion", "update the notion card for this branch", "describe these changes on notion".