Add setting to toggle subagent visibility in sidebar agent list #26
Description
Feature Request
Add a user-facing setting in Settings for "Show subagents in left hand side coding agents list" (default: off).
This gives users control over whether subagent sessions (e.g., Task tool agents spawned by Claude Code) appear in the sidebar's coding agents list. Related to #24.
Acceptance Criteria
- New toggle in Settings: "Show subagents in left hand side coding agents list"
- When off (default), subagent sessions are hidden from the sidebar agent list
- When on, all agent sessions (including subagents) are shown as they are today
- Setting persists in user config