feat(skills): wire session.Append into retrospective and trainer

internal/skills/trainer/handlers.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"time"
 
 	iexec "github.com/mathiasbq/supervisor/internal/exec"
 	"github.com/mathiasbq/supervisor/internal/session"
@@ -58,6 +59,7 @@ func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (
 	}
 
 	// ── Step 2: Writer agent (receives reader candidates) ────────────────────
+	t0 := time.Now()
 	writerTask := fmt.Sprintf(
 		"role: writer\nsession_id: %s\nbrain_dir: %s\n\nreader_summary: %s\nreader_candidates:\n%s",
 		a.SessionID, s.cfg.BrainDir, readerResult.Message, readerResult.RunnerOutput,
@@ -72,6 +74,18 @@ func (s *Skill) Handle(ctx context.Context, tool string, args json.RawMessage) (
 		return nil, fmt.Errorf("writer agent: %w", err)
 	}
 
+	_ = session.Append(s.cfg.SessionsDir, a.SessionID, session.Entry{
+		SessionID:   a.SessionID,
+		Timestamp:   time.Now(),
+		Skill:       "trainer",
+		Phase:       "trainer",
+		Attempts:    session.AttemptsFrom(writerResult.Attempts),
+		FinalStatus: writerResult.Status,
+		ModelUsed:   writerResult.ModelUsed,
+		DurationMs:  time.Since(t0).Milliseconds(),
+		Message:     writerResult.Message,
+	})
+
 	b, err := json.Marshal(writerResult)
 	if err != nil {
 		return nil, fmt.Errorf("marshal result: %w", err)