When a milestone has CONTEXT-DRAFT.md (phase: needs-discussion), the
dispatch table returned 'stop' — which made auto-mode exit. Running
/gsd again would re-enter auto → dispatch → stop → loop indefinitely.
The guided-flow already has a complete interactive handler for
needs-discussion (discuss from draft / start fresh / skip), but it was
never reached from the auto-mode entry path.
Added an early check in dispatchNextUnit: if phase is needs-discussion,
stop auto-mode gracefully and route to showSmartEntry() which handles
the discussion flow correctly.
Fixes#1170
a1ef04a5f3