T006: Add Certificate entities to DbContext

[Hemavathi15sg]

Phase 2: Foundational

Task: T006
Status: Not Started
Story: Foundational (blocking all user stories)
Blocked By: T002 (packages added), T006-T010 (entities created)

Description

Add Certificate domain entities to DbContext (CourseRegistrationDbContext.cs) with proper relationship configuration.

Acceptance Criteria

• DbSet added to DbContext
• DbSet added to DbContext
• DbSet added to DbContext
• One-to-zero-or-one relationship configured: CourseCompletion → Certificate
• One-to-many relationship configured: Certificate → CertificateVerification
• One-to-many relationship configured: Certificate → CertificateAuditLog
• Soft delete query filters applied (IsDeleted = 0) for Certificate entities
• DbContext recompiles with no errors

Effort Estimate

3 hours

References

• data-model.md: Entity Relationship Diagram section
• plan.md: Project Structure (Infrastructure/Data/)