Rules (text nodes only):

• 𓐝 then 𓃭 → insert <br> before 𓃭, caret stays after 𓐝
• 𓃭 then 𓐝 → insert <br> before 𓐝, caret stays after 𓃭

Lock effective advance turns off kerning ("kern" 0) so order-dependent tightening is reduced.