feat: add diagnostic interview loop

internal/workflows/runner.go

@@ -3,6 +3,7 @@ package workflows
 import (
 	"context"
 	"errors"
+	"strings"
 )
 
 var ErrNotImplemented = errors.New("workflow runner not implemented")
@@ -27,6 +28,7 @@ type GradeAnswerInput struct {
 	QuestionID string
 	AnswerID   string
 	AnswerText string
+	Concepts   []ConceptRef
 }
 
 type NextChallengeInput struct {
@@ -49,8 +51,49 @@ func (StubRunner) DiagnoseJobSeeker(context.Context, DiagnosticInput) (Diagnosti
 	return DiagnosticResult{}, ErrNotImplemented
 }
 
-func (StubRunner) GradeInterviewAnswer(context.Context, GradeAnswerInput) (GradedAnswer, error) {
-	return GradedAnswer{}, ErrNotImplemented
+func (StubRunner) GradeInterviewAnswer(_ context.Context, input GradeAnswerInput) (GradedAnswer, error) {
+	wordCount := len(strings.Fields(input.AnswerText))
+	overall := AnswerPartial
+	if wordCount >= 18 {
+		overall = AnswerSolid
+	}
+	if wordCount < 8 {
+		overall = AnswerMiss
+	}
+
+	grade := GradedAnswer{
+		AnswerID:   input.AnswerID,
+		QuestionID: input.QuestionID,
+		Concepts:   append([]ConceptRef(nil), input.Concepts...),
+		Scores: AnswerScores{
+			Correctness:        scoreFromWords(wordCount, 8),
+			Depth:              scoreFromWords(wordCount, 14),
+			Communication:      scoreFromWords(wordCount, 10),
+			ProductionJudgment: scoreFromWords(wordCount, 20),
+		},
+		Overall:   overall,
+		Strengths: []string{"Answer was captured and evaluated through the typed workflow boundary."},
+		Gaps:      []string{},
+		Evidence: []EvidenceRef{
+			{
+				Kind:       EvidenceAnswer,
+				ID:         input.AnswerID,
+				Quote:      input.AnswerText,
+				Confidence: 1,
+			},
+		},
+		FollowUp: FollowUpRecommendation{},
+	}
+
+	if overall == AnswerMiss || overall == AnswerPartial {
+		grade.Gaps = []string{"Answer needs more concrete reasoning and tradeoff discussion."}
+		grade.FollowUp = FollowUpRecommendation{
+			Needed:   true,
+			Question: "Can you give a concrete production example and explain the tradeoff?",
+			Purpose:  FollowUpRepair,
+		}
+	}
+	return grade, nil
 }
 
 func (StubRunner) ExtractLearningMemory(context.Context, GradedAnswer) (MemoryUpdateCandidate, error) {
@@ -64,3 +107,13 @@ func (StubRunner) SelectNextChallenge(context.Context, NextChallengeInput) (Next
 func (StubRunner) UpdateReadinessMap(context.Context, ReadinessUpdateInput) (ReadinessUpdate, error) {
 	return ReadinessUpdate{}, ErrNotImplemented
 }
+
+func scoreFromWords(wordCount int, target int) int {
+	if wordCount >= target {
+		return 4
+	}
+	if wordCount >= target/2 {
+		return 2
+	}
+	return 1
+}