Implement CommandZone - the main Qt graphics class for rendering and
interacting with command zones.
This commit brings together all previous components:
- Uses CommandZoneState for visibility management
- Uses CommandZoneLogic for card data handling
- Uses ZoneToggleButton for visibility controls
- Uses CommanderTaxCounter for tax display
- Uses z_values.h for proper visual layering
Zone modifications for command zone support:
- SelectZone: add command zone to zone selection
- StackZone: support command zone in stack operations
- TableZone: command zone positioning integration
- ViewZoneWidget: command zone viewing support
Integration tests verify:
- Counter parenting behavior
- Zone state coordination
- Full graphics stack interaction
