**Architecture Refactor (SOLID Principles):**
- Implement AdminDashboardController (REST API)
- Add dashboard summary endpoint
- Add upcoming filings endpoint
- Add recent inquiries endpoint
- Add monthly statistics endpoint
**Database Layer (Repository Pattern):**
- Extend IInquiryRepository with date range queries
- Implement CountByDateRangeAsync
- Implement CountByStatusAndDateAsync
- Extend InquiryRepository with new methods
**Service Layer (Single Responsibility):**
- Extend AdminDashboardService with API methods
- Add GetRecentInquiriesAsync
- Add GetMonthlyStatsAsync with caching
**Test Coverage:**
- Update FakeInquiryRepository mock with new methods
**SOLID Application:**
✓ Single Responsibility: Each class has one reason to change
✓ Open/Closed: Dashboard API can be extended without modifying existing code
✓ Dependency Inversion: Service depends on Repository abstraction
✓ Interface Segregation: API endpoints are focused and specific
Status: ✓ Compiles successfully (0 errors, 0 warnings)
Next phases:
- Add remaining API controllers (Announcement, Client, FAQ, TaxFiling)
- Refactor Blazor components to use API instead of services
- Implement JWT token refresh mechanism
- Add SignalR for change notifications
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>