Add protocol-based widget system following the MetricsProvider pattern:
- Create DashboardWidgetProviderProtocol in contracts/widgets.py
- Add WidgetAggregatorService in core to discover and aggregate widgets
- Implement MarketplaceWidgetProvider for recent_imports widget
- Implement TenancyWidgetProvider for recent_vendors widget
- Update admin dashboard to use widget_aggregator
- Add widget_provider field to ModuleDefinition
Architecture documentation:
- Add widget-provider-pattern.md with implementation guide
- Add cross-module-import-rules.md enforcing core/optional separation
- Update module-system.md with widget_provider and import rules
This enables modules to provide rich dashboard widgets without core modules
importing from optional modules, maintaining true module independence.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Samir Boulahtit
3e38db79aa