Add "Show MCP tool execution panels" sub-setting

[Jurij89]

Summary

• Add a "Show MCP tool execution panels" sub-setting under auto-approve in Settings > Tools & Plugins
• When disabled (default), auto-approved tools execute silently in the background with a continuous "Thinking..." indicator
• When enabled, tool panels (name, inputs, outputs) are shown in chat as before

Changes

• useSettings.tsx
  • Add showMcpToolExecutionPanels: boolean to Settings type
  • Default autoApproveMcpTools to true
  • Default showMcpToolExecutionPanels to false
• Checkbox.tsx
  • Add disabled prop (grays out + prevents interaction)
• McpAutoaproveForm.tsx
  • Dual-checkbox form
  • Sub-checkbox is indented and disabled when auto-approve is off
• settings.tsx
  • Persist both settings values
• chat.tsx
  • Auto-execute hidden tool calls via useEffect
  • Skip empty assistant messages
  • Show continuous Thinking indicator and disable input during hidden tool execution

Test Plan

• Panels hidden (default): Ask agent something that triggers tools → tools execute silently, continuous Thinking... shown, single agent response appears
• Panels enabled: Toggle setting on → tool panels appear (collapsed, auto-confirmed), same as previous behavior
• Auto-approve off: Sub-checkbox grays out; tools show manual confirmation UI regardless
• Multi-round tools: Multiple sequential tool calls → all execute silently, single final response
• No tools used: Plain text conversation → identical behavior to before
• Settings persist: Restart / re-login → values retained in AsyncStorage
• Start again: Resets all state cleanly