ACI-019: Session Lifecycle as Missing Primitive

Thesis

No AI coding tool provides a structured session lifecycle. Every tool assumes the session is a conversation that starts when you type and ends when you close the terminal. In practice, sessions need orientation (where are we?), planning (what are we doing?), execution, verification (did it work?), review (is it good?), finishing (update docs, commit), and handoff (prepare for the next session). This lifecycle is the atomic unit of agentic productivity, and it is missing from every tool.