feat(career): structured career profile foundation

Phase 3, schema layer. Relational children of CareerProfile — the editable master
career profile. See docs/architecture/career-profile-model.md.

- New entities (Models/CareerEntities.cs): CareerExperience, CareerEducation,
  CareerSkill, CareerProject, CareerCertification, CareerLanguage. Each carries
  OwnerUserId (tenant filter), a stable ItemKey (carried from the blob so future
  CV variants can reference items), and SortOrder. List fields persist as JSON
  string columns via [NotMapped] accessors — plain TEXT, reconciler-friendly.
- CareerProfile gains typed child collections + a LongTailJson column (contact,
  summary, interests, achievements, orgs, pubs, courses, custom sections,
  metadata). ProfileJson becomes a derived projection for legacy read paths.
- DbContext: DbSets + tenant query filters + ordered indexes; FK/cascade by
  convention via the typed collections.
- Migration hand-edited to add only the 6 new tables + LongTailJson; the
  scaffolder re-emitted four reconciler-owned tables (AiWorkspaceNotes,
  CareerProfiles, InterviewPrepNotes, CareerProfileVersions) which were stripped.
  The regenerated snapshot now includes them, closing the drift. Verified against
  a copy of the real dev DB: applies cleanly, no data loss.

Long tail (achievements/orgs/pubs/courses) starts as JSON; promotable to
relational later without a source-of-truth change. Source-of-truth flip stays
deferred; the blob is kept as a derived projection.

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

Data/JobTrackerContext.cs

@@ -34,6 +34,12 @@ namespace JobTrackerApi.Data
     public DbSet<UserSession> UserSessions => Set<UserSession>();
     public DbSet<CareerProfile> CareerProfiles => Set<CareerProfile>();
     public DbSet<CareerProfileVersion> CareerProfileVersions => Set<CareerProfileVersion>();
+    public DbSet<CareerExperience> CareerExperiences => Set<CareerExperience>();
+    public DbSet<CareerEducation> CareerEducations => Set<CareerEducation>();
+    public DbSet<CareerSkill> CareerSkills => Set<CareerSkill>();
+    public DbSet<CareerProject> CareerProjects => Set<CareerProject>();
+    public DbSet<CareerCertification> CareerCertifications => Set<CareerCertification>();
+    public DbSet<CareerLanguage> CareerLanguages => Set<CareerLanguage>();
     public DbSet<InterviewPrepNote> InterviewPrepNotes => Set<InterviewPrepNote>();
     public DbSet<AiWorkspaceNote> AiWorkspaceNotes => Set<AiWorkspaceNote>();
 
@@ -242,6 +248,17 @@ namespace JobTrackerApi.Data
             .HasForeignKey(x => x.CareerProfileId)
             .OnDelete(DeleteBehavior.Cascade);
 
+        // Phase 3: relational children of CareerProfile (the editable master profile).
+        // docs/architecture/career-profile-model.md. Same deny-on-null tenant filter as everything
+        // else; cascade-delete with the parent; indexed by (OwnerUserId, CareerProfileId, SortOrder)
+        // for the ordered per-profile reads the /career editor does.
+        ConfigureCareerChild<CareerExperience>(modelBuilder);
+        ConfigureCareerChild<CareerEducation>(modelBuilder);
+        ConfigureCareerChild<CareerSkill>(modelBuilder);
+        ConfigureCareerChild<CareerProject>(modelBuilder);
+        ConfigureCareerChild<CareerCertification>(modelBuilder);
+        ConfigureCareerChild<CareerLanguage>(modelBuilder);
+
         // Interview prep persistence (career-workspace-implementation-roadmap.md Phase F5).
         modelBuilder.Entity<InterviewPrepNote>()
             .HasQueryFilter(x => CurrentUserId != null && x.OwnerUserId == CurrentUserId);
@@ -272,5 +289,17 @@ namespace JobTrackerApi.Data
             .HasForeignKey(x => x.JobApplicationId)
             .OnDelete(DeleteBehavior.Cascade);
     }
+
+    // Common config for CareerProfile's relational children. The 1:many FK + cascade delete is
+    // wired by convention (each child's CareerProfileId + CareerProfile nav match the typed
+    // collection on CareerProfile); this adds the tenant query filter and the ordered read index.
+    private void ConfigureCareerChild<T>(ModelBuilder modelBuilder) where T : Models.CareerChildEntity
+    {
+        modelBuilder.Entity<T>()
+            .HasQueryFilter(x => CurrentUserId != null && x.OwnerUserId == CurrentUserId);
+
+        modelBuilder.Entity<T>()
+            .HasIndex(x => new { x.OwnerUserId, x.CareerProfileId, x.SortOrder });
+    }
 }
 }