The workspace map previously only cleaned up during Capture() calls,
meaning stale entries would accumulate indefinitely if no new captures
occurred. This adds:
- Background sweeper goroutine (Start/Stop lifecycle) that runs every 5
minutes to evict expired workspaces
- Configurable MaxWorkspaces and WorkspaceTTLMinutes in Config (defaults:
100 entries, 24h TTL) replacing hardcoded constants
- cleanup() now returns eviction count for observability logging
- Nil-config fallback to safe defaults
Fixes#54
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
0096a27c5b