Phases 3 & 4: Complete data access architecture migration

Phase 3 — eliminated ApplicationDbContext from all non-exempt controllers,
routing all data access through IUnitOfWork. Added IPlainRepository<T> for
the four platform entities (Announcement, BannedIp, DashboardTip, ReleaseNote)
that intentionally don't extend BaseEntity and therefore can't use the
constrained IRepository<T>. Added permanent-exception comments to the 18
controllers that legitimately retain direct DbContext access (Identity infra,
cross-tenant platform ops, bulk streaming exports).

Phase 4 — added EnforceDataAccessArchitecture() to Program.cs, a startup
gate that reflects over every Controller subclass and throws at boot if any
non-exempt controller injects ApplicationDbContext. The app cannot start with
a violation.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Core/Interfaces/IUnitOfWork.cs

@@ -14,14 +14,14 @@ public interface IUnitOfWork : IDisposable
     IRepository<AiItemPrediction> AiItemPredictions { get; }
 
     // Powder Insights
-    IRepository<PowderUsageLog> PowderUsageLogs { get; }
+    IPowderUsageLogRepository PowderUsageLogs { get; }
 
     // Core entities — typed repositories for complex domains
     ICustomerRepository Customers { get; }
     IJobRepository Jobs { get; }
     IRepository<JobDailyPriority> JobDailyPriorities { get; }
     IRepository<JobItem> JobItems { get; }
-    IRepository<JobItemCoat> JobItemCoats { get; }
+    IJobItemCoatRepository JobItemCoats { get; }
     IRepository<JobItemPrepService> JobItemPrepServices { get; }
     IRepository<JobChangeHistory> JobChangeHistories { get; }
     IRepository<JobPrepService> JobPrepServices { get; }
@@ -32,13 +32,13 @@ public interface IUnitOfWork : IDisposable
     IRepository<QuoteItemPrepService> QuoteItemPrepServices { get; }
     IRepository<QuoteChangeHistory> QuoteChangeHistories { get; }
     IRepository<InventoryItem> InventoryItems { get; }
-    IRepository<InventoryTransaction> InventoryTransactions { get; }
+    IInventoryTransactionRepository InventoryTransactions { get; }
     IRepository<Equipment> Equipment { get; }
     IRepository<OvenCost> OvenCosts { get; }
     IRepository<CompanyBlastSetup> BlastSetups { get; }
     IRepository<MaintenanceRecord> MaintenanceRecords { get; }
     IRepository<Vendor> Vendors { get; }
-    IRepository<JobPhoto> JobPhotos { get; }
+    IJobPhotoRepository JobPhotos { get; }
     IRepository<JobNote> JobNotes { get; }
     IRepository<CustomerNote> CustomerNotes { get; }
     IRepository<JobStatusHistory> JobStatusHistory { get; }
@@ -97,13 +97,21 @@ public interface IUnitOfWork : IDisposable
     IRepository<SubscriptionPlanConfig> SubscriptionPlanConfigs { get; }
 
     // Job Templates
-    IRepository<JobTemplate> JobTemplates { get; }
+    IJobTemplateRepository JobTemplates { get; }
     IRepository<JobTemplateItem> JobTemplateItems { get; }
     IRepository<JobTemplateItemCoat> JobTemplateItemCoats { get; }
     IRepository<JobTemplateItemPrepService> JobTemplateItemPrepServices { get; }
 
+    // Platform content (SuperAdmin-managed, no tenant filter, no soft delete)
+    IPlainRepository<Announcement> Announcements { get; }
+    IPlainRepository<BannedIp> BannedIps { get; }
+    IPlainRepository<DashboardTip> DashboardTips { get; }
+    IRepository<InAppNotification> InAppNotifications { get; }
+    IPlainRepository<ReleaseNote> ReleaseNotes { get; }
+
     // Bug Reports
     IRepository<BugReport> BugReports { get; }
+    IRepository<BugReportAttachment> BugReportAttachments { get; }
 
     // Contact Us
     IRepository<ContactSubmission> ContactSubmissions { get; }