docs: track backend architecture-refactor findings

Starting point for the ARCHITECTURE_AND_CODE_QUALITY.md cleanup pass: a
verified (not grep-only) list of layering violations, validation coverage
gaps against the existing FluentValidation pattern, and N+1/query-shape
issues found so far, plus what was checked and ruled out.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/refactor-backend-findings.md

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+# Backend architecture refactor — findings
+
+Tracking doc for `refactor/backend-architecture-cleanup`. Each item is verified
+against the actual code (not just a grep hit) before being listed here.
+Checked off as fixed, with tests, on this branch.
+
+## 1. Layering / dependency-injection violations
+
+- [ ] `AssetController` injects `UserManager<ApplicationUser>` via constructor
+      but never uses it anywhere in the file — dead dependency, remove it.
+- [ ] `ContactController` depends on both `IContactService` **and**
+      `ILocationService` and implements full Location CRUD (`GetAllLocationsAsync`,
+      `CreateLocationAsync`, `UpdateLocationAsync`, `DeleteLocationAsync`,
+      `GetLocationsPagedAsync`) even though a dedicated `LocationController`
+      with the same `ILocationService` already exists. Move the Location
+      endpoints out of `ContactController` into `LocationController`; a
+      Contact controller should depend only on `IContactService`.
+- [ ] `ArchitectureTests` (G2) currently passes with 0 failures — dependency
+      *direction* is otherwise clean (no controller/service injects
+      `DbContext`/`IConfiguration`/a concrete class). Re-run after each fix
+      above to confirm it stays green.
+
+## 2. Validation coverage gap
+
+Established pattern: `I{Action}{Feature}Validation : IValidator<{Dto}>` +
+`{Action}{Feature}Validation : AbstractValidator<{Dto}>` in
+`SeaHaven.Services/Validation/`, injected into the owning business service
+(see `LocationValidation.cs` / `LocationService`). Confirmed: **validation
+stays in the service layer** (not moved to data services) — only extending
+coverage to features that lack it.
+
+Have a validator today: Account, Asset, Contact, Dispatch, Employee, FollowUp,
+Location, PMSchedule, Vendor, WorkOrder, WorkOrderBoardCreate.
+
+Confirmed missing (real external Create/Update DTO, no validator):
+- [ ] `CalendarService.CreateEventAsync` / `UpdateEventAsync`
+- [ ] `CompletionDocTemplateService.CreateAsync` / `UpdateAsync`
+- [ ] `QuotesService.CreateQuoteAsync` / `UpdateQuoteAsync`
+- [ ] `ServicesRegistryService.CreateAsync` / `UpdateAsync`
+- [ ] `TaskListTemplateService.CreateAsync` / `UpdateAsync`
+- [ ] `TeamMemberInviteService.CreateAsync`
+- [ ] `TeamMemberService.CreateAsync` / `UpdateAsync`
+- [ ] `VendorCompanyRosterService.CreateRosterAsync`
+- [ ] `VendorOperationsService.UpdateAvailabilityAsync` / `UpdateCommercialStatusAsync`
+- [ ] `VendorPortalService.UpdateChecklistItemAsync`
+- [ ] `WorkOrderCommentService.UpdateCommentAsync`
+- [ ] `WorkOrderDispatchService.UpdateDispatchAsync` / `UpdateChecklistItemAsync`
+- [ ] `WorkOrderMediaService.UpdateMediaCategoryAsync`
+- [ ] `WorkOrderPocService.UpdatePocAsync`
+- [ ] `WorkOrderUpliftService.CreateAsync`
+- [ ] `DropdownOptionsService.CreateAsync` / `UpdateAsync`
+- [ ] `AuthenticationService.UpdateProfileAsync`
+
+Ruled out (internal/no external DTO, not a validator candidate):
+`AuthenticationService.CreateSessionAsync`, `VendorPortalTokenService.GetOrCreateActiveTokenAsync`,
+`WorkOrderAccountResolver` (no real Create/Update method; grep false positive).
+
+## 3. N+1 / query-shape issues (verified, not grep-only)
+
+- [ ] **`WorkOrderService.DeleteWorkOrderCascadeAsync`** loads all comments
+      then calls `_commentDataService.DeleteAsync(comment.Id)` once per
+      comment. `CommentDataService.DeleteAsync` does its own `GetByIdAsync`
+      (1 SELECT) + `SaveChangesAsync` (1 commit) **per call** — N comments =
+      2N round trips and N separate commits, breaking the one-commit
+      convention (§4) as well as being slow. Fix: add a batch delete
+      (`DeleteAllForWorkOrderAsync` via `ExecuteDeleteAsync`, or load once +
+      `RemoveRange` + one `SaveChangesAsync`) and call it once.
+- [ ] **`WorkOrderService.SaveAttachmentsAndPhotos`** loops over uploaded
+      attachments calling `_workOrderDataService.AddWorkOrderAttachmentAsync`
+      per file; that method does `AddAsync` + `SaveChangesAsync` **per call** —
+      N attachments = N separate commits. Fix: collect the `WorkOrderAttachments`
+      entities in the loop (file storage save can stay per-file — that's I/O,
+      not DB), then add a batch method that calls `AddRangeAsync` + one
+      `SaveChangesAsync`.
+- [ ] **`VendorCompanyRosterDataService`** (3 call sites: roster update,
+      create, and a third) loads `existingTechnicians` once via a single
+      query, then does `existingTechnicians.FirstOrDefault(e => e.Id == ...)`
+      **inside** a loop over the incoming roster — O(n·m) in-memory scan.
+      Fix: build `existingTechnicians.ToDictionary(e => e.Id)` once before the
+      loop and `TryGetValue` inside it — O(n+m).
+
+## Ruled out during the sweep (false positives / legitimate design)
+
+- `WorkOrderAuditDataService.PersistAsync`: the `foreach` detaches conflicting
+  entries from a caught `DbUpdateException`; the retry `SaveChangesAsync` is
+  after the loop, not inside it. Not an issue.
+- `VendorPortalTokenService.RotateAsync` / `RevokeAllAsync`: the `foreach`
+  only mutates already-tracked entities in memory (`t.RevokedAt = now`); the
+  single `SaveChangesAsync` is after the loop. Not an issue.
+- `WorkOrderWeekRolledService`: calls `TryProcessWeekRolledAsync` once per
+  work order inside a batch-job loop, each with its own try/catch. This is
+  intentional per-item fault isolation for a background job — collapsing it
+  into one transaction would change the failure semantics (one bad work order
+  would abort the whole batch). Not an issue; do not "optimize" this away.
+- Legacy `SeaHavenIndustries` project (old Blazor admin app) has its own
+  ad-hoc `Service` classes touching `DbContext` directly, violating the
+  layering model wholesale — but it is being actively sunset (see commit
+  `64ca9e0`, "add legacy deprecation middleware and Blazor WO sunset guard").
+  Out of scope: refactoring code on its way out is wasted effort.
+
+## Still to audit
+
+- Cancellation-token forwarding (§6) on data-service methods — not yet swept.
+- Error disclosure (§5) — spot-check only so far (`VendorCompanyRosterController`
+  catches `DbUpdateConcurrencyException` directly; check whether that
+  duplicates the existing `ConcurrencyExceptionFilter`).
+- Tenant-scope derivation (§2) — not yet swept.
+- `AsNoTracking()` coverage on read-only data-service queries — not yet swept.