Architect terminal should survive Tower restarts (shellper persistence)

[waleedkadous]

Bug Description

Builder terminals survive Tower restarts via shellper-backed PTY sessions, but the architect terminal does not. When Tower is stopped and restarted (e.g., for a package update), builders reconnect seamlessly while the architect session is lost.

Steps to Reproduce

1. af dash start — start architect dashboard
2. Open architect terminal, begin working
3. af tower stop && af tower start — restart Tower
4. Architect terminal is gone; builders survive

Expected Behavior

Architect terminal should be shellper-backed and survive Tower restarts, just like builder terminals do.

Actual Behavior

Architect terminal dies on Tower restart. User must re-run af dash start to get a new session.

Context

Shellper (Spec 0104) was designed for terminal session persistence across restarts. It works correctly for builder sessions spawned via af spawn, but the architect terminal created by af dash start appears to not go through the same shellper path.

[waleedkadous]

On it! Working on a fix now.