fix(jobs): derive attachment checklist flags from actual Attachments

Backlog item 4 (Wave 3, first sub-item). HasResume/HasCoverLetter/HasPortfolio/
HasOtherAttachment were manually-editable checkboxes in EditJobDialog,
completely independent of whether a file was actually attached -- classic
drift: mark 'resume ready' by hand, later delete the resume attachment, flag
stays stuck true forever. User confirmed (asked directly, since removing the
manual-override capability is a product decision, not purely technical):
make them fully computed from Attachments, no manual override.

- AttachmentsController.RecomputeAttachmentFlagsAsync: the single place these
  four fields get written now, called after every attachment mutation
  (upload, delete, Purpose change) that could affect them. Deliberately kept
  as persisted columns (not [NotMapped] computed properties reading the
  Attachments navigation collection) -- ~15 query sites build JobApplication
  DTOs without .Include(Attachments), so a live-computed property would
  silently return false everywhere instead of throwing, the worst kind of
  bug. Recomputing at the one write funnel avoids touching any read path.
- Removed HasResume/etc from CreateJobApplicationRequest/
  UpdateJobApplicationRequest -- no longer client-settable.
- EditJobDialog: removed the manual checkboxes, kept the (now genuinely
  accurate) read-only status chips.
- AddJobModal: stopped sending has*-flags at job-creation time; the
  follow-up attachment upload call now sets them correctly via the same
  recompute path.

Caught a real bug while testing this: the Purpose-change path recomputed
before saving the Purpose change, so a fresh query missed the pending edit
and the flags never updated. Fixed by committing the mutation before
recomputing.

3 new backend tests (purpose-change sets flag, delete clears flag,
non-primary purpose counts as "other"). 172/172 backend, 25/25 frontend
suites (57 tests) green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

JobTrackerApi.Tests/AttachmentFlagsRecomputeTests.cs

@@ -0,0 +1,111 @@
+using JobTrackerApi.Controllers;
+using JobTrackerApi.Data;
+using JobTrackerApi.Models;
+using JobTrackerApi.Services;
+using JobTrackerApi.Tests.TestSupport;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Moq;
+using Xunit;
+
+namespace JobTrackerApi.Tests;
+
+// JobApplication.HasResume/HasCoverLetter/HasPortfolio/HasOtherAttachment are derived from
+// Attachment rows (backlog Wave 3), not manually settable. These tests exercise the single
+// place they're written: AttachmentsController's Purpose-change and Delete paths.
+public sealed class AttachmentFlagsRecomputeTests
+{
+    [Fact]
+    public async Task Changing_purpose_to_resume_sets_HasResume()
+    {
+        await using var db = TestHostFactory.CreateInMemoryDb();
+        var (job, attachment) = await SeedJobWithAttachmentAsync(db, purpose: "other");
+        var controller = CreateController(db);
+
+        var result = await controller.Rename(attachment.Id, new AttachmentsController.UpdateAttachmentRequest(null, "resume", null), CancellationToken.None);
+
+        Assert.IsType<NoContentResult>(result);
+        var updated = await db.JobApplications.SingleAsync(j => j.Id == job.Id);
+        Assert.True(updated.HasResume);
+        Assert.True(updated.HasOtherAttachment == false);
+    }
+
+    [Fact]
+    public async Task Deleting_the_only_resume_attachment_clears_HasResume()
+    {
+        await using var db = TestHostFactory.CreateInMemoryDb();
+        var (job, attachment) = await SeedJobWithAttachmentAsync(db, purpose: "resume");
+        var controller = CreateController(db);
+
+        var result = await controller.Delete(attachment.Id, CancellationToken.None);
+
+        Assert.IsType<NoContentResult>(result);
+        var updated = await db.JobApplications.SingleAsync(j => j.Id == job.Id);
+        Assert.False(updated.HasResume);
+    }
+
+    [Fact]
+    public async Task Attachment_with_case_study_purpose_counts_as_other()
+    {
+        await using var db = TestHostFactory.CreateInMemoryDb();
+        var (job, attachment) = await SeedJobWithAttachmentAsync(db, purpose: "resume");
+        var controller = CreateController(db);
+
+        await controller.Rename(attachment.Id, new AttachmentsController.UpdateAttachmentRequest(null, "case-study", null), CancellationToken.None);
+
+        var updated = await db.JobApplications.SingleAsync(j => j.Id == job.Id);
+        Assert.False(updated.HasResume);
+        Assert.True(updated.HasOtherAttachment);
+    }
+
+    private static async Task<(JobApplication Job, Attachment Attachment)> SeedJobWithAttachmentAsync(JobTrackerContext db, string purpose)
+    {
+        var company = new Company { Name = "Acme", OwnerUserId = "user-1" };
+        db.Companies.Add(company);
+        await db.SaveChangesAsync();
+
+        var job = new JobApplication { JobTitle = "Backend Developer", CompanyId = company.Id, OwnerUserId = "user-1" };
+        db.JobApplications.Add(job);
+        await db.SaveChangesAsync();
+
+        var attachment = new Attachment
+        {
+            JobApplicationId = job.Id,
+            FileName = "file.pdf",
+            FilePath = Path.Combine(Path.GetTempPath(), $"jobtracker-attachment-test-{Guid.NewGuid():N}.pdf"),
+            FileType = "application/pdf",
+            FileSize = 100,
+            Purpose = purpose,
+        };
+        db.Attachments.Add(attachment);
+        await db.SaveChangesAsync();
+
+        job.HasResume = purpose == "resume";
+        job.HasOtherAttachment = purpose is not ("resume" or "cover-letter" or "portfolio");
+        await db.SaveChangesAsync();
+
+        return (job, attachment);
+    }
+
+    private static AttachmentsController CreateController(JobTrackerContext db)
+    {
+        var tempRoot = Path.Combine(Path.GetTempPath(), $"jobtracker-attachments-tests-{Guid.NewGuid():N}");
+        Directory.CreateDirectory(tempRoot);
+
+        var config = new ConfigurationBuilder()
+            .AddInMemoryCollection(new Dictionary<string, string?> { ["Data:Root"] = tempRoot })
+            .Build();
+
+        var env = new Mock<IHostEnvironment>();
+        env.SetupGet(x => x.ContentRootPath).Returns(tempRoot);
+        var paths = new AppPaths(config, env.Object);
+
+        return new AttachmentsController(paths, db)
+        {
+            ControllerContext = new ControllerContext { HttpContext = new DefaultHttpContext() }
+        };
+    }
+}

JobTrackerApi.Tests/JobApplicationsEndpointBehaviorTests.cs

@@ -202,11 +202,7 @@ public sealed class JobApplicationsEndpointBehaviorTests
             CoverLetterText: null,
             JobUrl: null,
             DateApplied: null,
-            FeedbackRequestedAt: null,
-            HasResume: null,
-            HasCoverLetter: null,
-            HasPortfolio: null,
-            HasOtherAttachment: null);
+            FeedbackRequestedAt: null);
 
         var result = await controller.Create(request, CancellationToken.None);
 
@@ -255,10 +251,6 @@ public sealed class JobApplicationsEndpointBehaviorTests
             SalaryPeriod: "fortnight",
             NextAction: null,
             FollowUpAt: null,
-            HasResume: null,
-            HasCoverLetter: null,
-            HasPortfolio: null,
-            HasOtherAttachment: null,
             Notes: null,
             Description: null,
             TranslatedDescription: null,