Auto-spawned discuss/plan/refine agents were invisible because:
1. listInitiatives only filtered for mode='detail' agents
2. deriveInitiativeActivity returned 'idle' for zero phases before
checking for active agents
Broadened agent filter to all architect modes (discuss, plan, detail,
refine), moved active agent check before zero-phases early return, and
added 'discussing'/'refining' activity states with pulsing indicators.
3d04cb2081