fix: usar fechas relativas en TestCleanOldLogs

Las fechas hardcoded (2026-02-24, 2026-03-01, 2026-03-06) quedaron fuera
del periodo de retención de 7 días al avanzar el calendario. Ahora el test
calcula las fechas relativas a time.Now() para que no caduque.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

shell/logger/cleanup_test.go

@@ -13,18 +13,22 @@ func TestCleanOldLogs(t *testing.T) {
 	agentDir := filepath.Join(dir, "bot1")
 	os.MkdirAll(agentDir, 0o755)
 
-	// Create files: 10 days ago, 5 days ago, today.
+	now := time.Now().UTC()
+	oldDate := now.AddDate(0, 0, -10).Format("2006-01-02")   // 10 days ago → should be removed
+	recentDate := now.AddDate(0, 0, -5).Format("2006-01-02") // 5 days ago → should remain
+	todayDate := now.Format("2006-01-02")                     // today → should remain
+
 	files := []string{
-		"2026-02-24.jsonl",
-		"2026-02-24.jsonl.gz",
-		"2026-03-01.jsonl",
-		"2026-03-06.jsonl",
+		oldDate + ".jsonl",
+		oldDate + ".jsonl.gz",
+		recentDate + ".jsonl",
+		todayDate + ".jsonl",
 	}
 	for _, f := range files {
 		os.WriteFile(filepath.Join(agentDir, f), []byte("{}"), 0o644)
 	}
 
-	// Retain 7 days → should remove 2026-02-24 files.
+	// Retain 7 days → should remove files older than 7 days.
 	cleanOldLogs(dir, "bot1", 7)
 
 	remaining, _ := os.ReadDir(agentDir)
@@ -33,17 +37,17 @@ func TestCleanOldLogs(t *testing.T) {
 		names[e.Name()] = true
 	}
 
-	if names["2026-02-24.jsonl"] {
-		t.Error("2026-02-24.jsonl should have been removed")
+	if names[oldDate+".jsonl"] {
+		t.Errorf("%s.jsonl should have been removed", oldDate)
 	}
-	if names["2026-02-24.jsonl.gz"] {
-		t.Error("2026-02-24.jsonl.gz should have been removed")
+	if names[oldDate+".jsonl.gz"] {
+		t.Errorf("%s.jsonl.gz should have been removed", oldDate)
 	}
-	if !names["2026-03-01.jsonl"] {
-		t.Error("2026-03-01.jsonl should still exist")
+	if !names[recentDate+".jsonl"] {
+		t.Errorf("%s.jsonl should still exist", recentDate)
 	}
-	if !names["2026-03-06.jsonl"] {
-		t.Error("2026-03-06.jsonl should still exist")
+	if !names[todayDate+".jsonl"] {
+		t.Errorf("%s.jsonl should still exist", todayDate)
 	}
 }