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.Infrastructure/Repositories/JobTemplateRepository.cs

@@ -0,0 +1,47 @@
+using Microsoft.EntityFrameworkCore;
+using PowderCoating.Core.Entities;
+using PowderCoating.Core.Interfaces.Repositories;
+using PowderCoating.Infrastructure.Data;
+
+namespace PowderCoating.Infrastructure.Repositories;
+
+/// <summary>
+/// Typed repository for <see cref="JobTemplate"/> that provides domain-specific multi-level
+/// include queries that the generic <see cref="Repository{T}"/> cannot express.
+/// The base class handles all standard CRUD operations; this class adds the read queries
+/// that require ThenInclude chains for items, coats, and prep services.
+/// </summary>
+public class JobTemplateRepository : Repository<JobTemplate>, IJobTemplateRepository
+{
+    public JobTemplateRepository(ApplicationDbContext context) : base(context) { }
+
+    /// <inheritdoc/>
+    public async Task<JobTemplate?> LoadForDetailsAsync(int id)
+    {
+        return await _context.JobTemplates
+            .Where(t => t.Id == id && !t.IsDeleted)
+            .Include(t => t.Customer)
+            .Include(t => t.Items.Where(i => !i.IsDeleted))
+                .ThenInclude(i => i.Coats.Where(c => !c.IsDeleted))
+                    .ThenInclude(c => c.InventoryItem)
+            .Include(t => t.Items.Where(i => !i.IsDeleted))
+                .ThenInclude(i => i.PrepServices.Where(p => !p.IsDeleted))
+                    .ThenInclude(p => p.PrepService)
+            .FirstOrDefaultAsync();
+    }
+
+    /// <inheritdoc/>
+    public async Task<List<JobTemplate>> GetAllActiveWithFullIncludesAsync()
+    {
+        return await _context.JobTemplates
+            .Where(t => !t.IsDeleted && t.IsActive)
+            .Include(t => t.Customer)
+            .Include(t => t.Items.Where(i => !i.IsDeleted))
+                .ThenInclude(i => i.Coats.Where(c => !c.IsDeleted))
+            .Include(t => t.Items.Where(i => !i.IsDeleted))
+                .ThenInclude(i => i.PrepServices.Where(p => !p.IsDeleted))
+                    .ThenInclude(p => p.PrepService)
+            .OrderBy(t => t.Name)
+            .ToListAsync();
+    }
+}