Continuing: #270465

Parent issue tracking the proposed changes required to support multi-agent workflows:

High confidence, low(er) effort:
✅ Session titles: #277537 (UXE)
✅ Delegation menu: #277555 (UXE)
✅ Agent session default position: #277558 (Eng)

High confidence, high effort:
✅ Progress streaming: #277560 (Eng)
✅ Agent Session as Chat empty state: #277563 (Eng)

Low(er) confidence, requires more validation:
➡️ Show new session inline after delegation: #277568 (Eng)