feat: bot activity monitoring in UI (agent trace view)

[jlunder00]

Background

The bot orchestrator now runs multi-phase, multi-agent pipelines (think_and_plan → subagent dispatches → evaluate/retry → memory consolidation → final response). When a complex request triggers 3 retry rounds across 4 anchors, there's currently no way to see what's happening except waiting for the final Telegram message.

Goal

Real-time visibility into orchestrator activity in the web UI, push-based via the existing WebSocket connection (no polling).

Proposed design

Backend:

• Bot emits structured events via _emit_event(phase, **data) → POST /api/bot-event → manager.broadcast()
• Event types: bot_thinking, bot_dispatching (with dispatch N/M, action, anchor_id), bot_evaluating, bot_memory, bot_done
• Subagent reports included in bot_done event

Frontend:

• Handle new WS event types in existing listener
• Live activity strip/panel showing current phase + progress
• Collapsible per-dispatch detail (action, anchor, report, mutations applied)
• Full agent trace for completed requests (expandable history)

Spec needed before implementation

• What level of detail to show per subagent (just report? mutations list? prompt used?)
• How long to retain traces (session only? persist in DB?)
• UI placement (sidebar panel? inline in plan view? floating toast?)
• Whether failed dispatches and retry rounds should be visually distinct