feat: add learner memory ingestion

internal/interview/service.go

@@ -8,6 +8,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"tutor/internal/learnermemory"
 	"tutor/internal/workflows"
 )
 
@@ -16,11 +17,12 @@ var ErrQuestionNotFound = errors.New("diagnostic question not found")
 type Service struct {
 	store  Store
 	runner workflows.Runner
+	memory *learnermemory.Service
 	ids    atomic.Uint64
 }
 
-func NewService(store Store, runner workflows.Runner) *Service {
-	return &Service{store: store, runner: runner}
+func NewService(store Store, runner workflows.Runner, memory *learnermemory.Service) *Service {
+	return &Service{store: store, runner: runner, memory: memory}
 }
 
 func (s *Service) CreateSession(_ context.Context, input CreateSessionInput) (Session, error) {
@@ -45,6 +47,16 @@ func (s *Service) CreateSession(_ context.Context, input CreateSessionInput) (Se
 		Questions:         BackendDeveloperQuestions(),
 		CreatedAt:         time.Now().UTC(),
 	}
+	if s.memory != nil {
+		if _, err := s.memory.EnsureProfile(learnermemory.ProfileInput{
+			UserID:            session.UserID,
+			TargetRole:        session.TargetRole,
+			Stack:             session.Stack,
+			InterviewTimeline: session.InterviewTimeline,
+		}); err != nil {
+			return Session{}, err
+		}
+	}
 	return s.store.Create(session)
 }
 
@@ -84,6 +96,15 @@ func (s *Service) SubmitAnswer(ctx context.Context, input SubmitAnswerInput) (An
 		return Answer{}, err
 	}
 	answer.Grade = grade
+	if s.memory != nil {
+		candidate, err := s.runner.ExtractLearningMemory(ctx, grade)
+		if err != nil {
+			return Answer{}, err
+		}
+		if err := s.memory.ApplyCandidate(candidate); err != nil {
+			return Answer{}, err
+		}
+	}
 
 	session.Answers = append(session.Answers, answer)
 	if answeredQuestionCount(session.Answers) >= len(session.Questions) {

internal/interview/service_test.go

@@ -4,11 +4,13 @@ import (
 	"context"
 	"testing"
 
+	"tutor/internal/learnermemory"
 	"tutor/internal/workflows"
 )
 
 func TestDiagnosticSessionAnswerFlow(t *testing.T) {
-	service := NewService(NewMemoryStore(), workflows.NewStubRunner())
+	memory := learnermemory.NewService(learnermemory.NewMemoryStore())
+	service := NewService(NewMemoryStore(), workflows.NewStubRunner(), memory)
 
 	session, err := service.CreateSession(context.Background(), CreateSessionInput{
 		UserID:     "user-1",
@@ -53,10 +55,22 @@ func TestDiagnosticSessionAnswerFlow(t *testing.T) {
 	if len(loaded.Answers) != 1 {
 		t.Fatalf("answers = %d, want 1", len(loaded.Answers))
 	}
+
+	snapshot, err := memory.Snapshot(session.UserID)
+	if err != nil {
+		t.Fatalf("memory snapshot error: %v", err)
+	}
+	if len(snapshot.Mastery) == 0 {
+		t.Fatal("expected memory mastery updates")
+	}
+	if len(snapshot.Mastery[0].Evidence) == 0 {
+		t.Fatal("expected memory evidence")
+	}
 }
 
 func TestDiagnosticSessionCompletesAfterAllQuestionsAnswered(t *testing.T) {
-	service := NewService(NewMemoryStore(), workflows.NewStubRunner())
+	memory := learnermemory.NewService(learnermemory.NewMemoryStore())
+	service := NewService(NewMemoryStore(), workflows.NewStubRunner(), memory)
 
 	session, err := service.CreateSession(context.Background(), CreateSessionInput{
 		UserID:     "user-1",