[Dev UI] SessionFlow runner - Inline elements

[ssbushi]

Overview

• Support tool interrupts inline with SessionFlow conversation
• Support errors (with resumes, if available) inline with conversations.

Notes

https://docs.google.com/document/d/14EqT5xzeDP5G6--Zfe38KIf39PX1T7MBcNWlfThf3fk/edit?tab=t.0