R1:5349d6bd5c09

Add Summary and Repository EditEngine fields + Modular Transactions to Differential

Summary: Ref T11114. These are unambiguous and always-enabled.

Test Plan: {F2117777}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11114

Differential Revision: https://secure.phabricator.com/D17047