- ToolCard: remove emoji header, collapse Arguments behind <details>,
  render results with structured JSON (color-coded values) or markdown
  detection for string outputs.
- SubagentStep: mirror ToolCard compact layout with same helpers.
- AssistantMessage: fold tool lists when >3 tools — show last 3 + summary
  bar with count and toggle icon-button; TransitionGroup for smooth
  expand/collapse animations.
- Plan card: switch accent color from info to secondary, compact sizing.
- Thinking card: compact sizing, remove bottom margin.
- app.scss: add details::details-content animation, fix nested chevron
  rotation in subagent steps, adjust margins and input-bar padding.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Previously PlanningStatus/PlanReady had no is_subagent flag, so subagent
planning spinners and plan cards rendered as top-level Navi planning UI.

Backend:
- Add is_subagent field to PlanningStatus and PlanReady events
- _run_planning accepts is_subagent param, passes it through all yields
- run_ephemeral calls _run_planning with is_subagent=True
- websocket.py forwards is_subagent in planning_status and plan_ready messages

Frontend (chat.js):
- onPlanningStatus: if is_subagent, set planningLabel on the last spawn_agent
  card instead of msg.statusLabel
- onPlanReady: if is_subagent, push plan into spawn card steps and clear
  planningLabel; otherwise behave as before

Frontend (ToolCard.vue):
- Render subagent-planning-indicator (spinner + label) when planningLabel set
- Render plan cards inside subagent steps using the same plan-card pattern

Also includes leftover session changes: spawn_agent default 40 in description
and manual, updated manual content.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- client/ → old_webclient/ (vanilla JS client preserved as reference)
- webclient/ — new Vue 3 + Pinia webclient (source + dist build)
- vite.config.js: outDir changed to webclient/dist/
- main.py: serve /assets and /images from webclient/dist/,
  index.html from webclient/dist/index.html
- .gitignore: exclude webclient/node_modules/, include webclient/dist/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>