improve(session): redesign /session list display for clarity

- Show summary (truncated to 40 chars) as primary identifier
- Move #id to trailing parentheses to reduce visual noise
- Use relative time (2h ago) instead of absolute timestamps
- Add Summary field to SessionMeta, populated from Session.Summary
- List row number = resume parameter, zero ambiguity

Before: 1. [*] agent:main:telegram:direct:300900269#10 | updated: 2026-03-01 23:22 | messages: 8
After:  1. [*] Discussing React performance...  | 8 msgs | 2h ago (#10)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/commands/cmd_session.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/sipeed/picoclaw/pkg/session"
 )
@@ -72,20 +73,65 @@ func sessionResumeHandler() Handler {
 
 func formatSessionList(list []session.SessionMeta) string {
 	lines := make([]string, 0, len(list)+1)
-	lines = append(lines, "Sessions for current chat:")
+	lines = append(lines, "Sessions:")
+	now := time.Now()
 	for _, item := range list {
 		activeMarker := "   "
 		if item.Active {
-			activeMarker = "*"
+			activeMarker = "[*]"
 		}
-		updated := "-"
+
+		summary := truncateSummary(item.Summary, 40)
+
+		age := "-"
 		if !item.UpdatedAt.IsZero() {
-			updated = item.UpdatedAt.Format("2006-01-02 15:04")
+			age = relativeTime(now, item.UpdatedAt)
 		}
+
+		tag := extractSessionTag(item.SessionKey)
+
 		lines = append(lines, fmt.Sprintf(
-			"%d. [%s] %s | updated: %s | messages: %d",
-			item.Ordinal, activeMarker, item.SessionKey, updated, item.MessageCnt,
+			"%d. %s %s | %d msgs | %s (%s)",
+			item.Ordinal, activeMarker, summary, item.MessageCnt, age, tag,
 		))
 	}
 	return strings.Join(lines, "\n")
 }
+
+func truncateSummary(s string, maxLen int) string {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return "(no summary)"
+	}
+	s = strings.ReplaceAll(s, "\n", " ")
+	if len(s) <= maxLen {
+		return s
+	}
+	return s[:maxLen] + "..."
+}
+
+// extractSessionTag returns the "#N" suffix from a session key, or "#1" for
+// the initial session that has no "#" separator.
+func extractSessionTag(sessionKey string) string {
+	if i := strings.LastIndex(sessionKey, "#"); i >= 0 {
+		return "#" + sessionKey[i+1:]
+	}
+	return "#1"
+}
+
+func relativeTime(now, t time.Time) string {
+	d := now.Sub(t)
+	switch {
+	case d < time.Minute:
+		return "just now"
+	case d < time.Hour:
+		m := int(d.Minutes())
+		return fmt.Sprintf("%dm ago", m)
+	case d < 24*time.Hour:
+		h := int(d.Hours())
+		return fmt.Sprintf("%dh ago", h)
+	default:
+		days := int(d.Hours() / 24)
+		return fmt.Sprintf("%dd ago", days)
+	}
+}

pkg/commands/session_handlers_test.go

@@ -3,6 +3,7 @@ package commands
 import (
 	"context"
 	"errors"
+	"strings"
 	"testing"
 	"time"
 
@@ -119,6 +120,7 @@ func TestSessionHandlers_SessionList(t *testing.T) {
 				UpdatedAt:  time.Date(2026, 3, 1, 9, 7, 0, 0, time.UTC),
 				MessageCnt: 4,
 				Active:     true,
+				Summary:    "Discussing React performance",
 			},
 		},
 	}
@@ -135,8 +137,11 @@ func TestSessionHandlers_SessionList(t *testing.T) {
 	if res.Outcome != OutcomeHandled {
 		t.Fatalf("outcome=%v, want=%v", res.Outcome, OutcomeHandled)
 	}
-	if reply != "Sessions for current chat:\n1. [*] scope#3 | updated: 2026-03-01 09:07 | messages: 4" {
-		t.Fatalf("reply=%q", reply)
+	// Check key elements: header, active marker, summary, message count, session tag
+	for _, want := range []string{"Sessions:", "[*]", "Discussing React performance", "4 msgs", "(#3)"} {
+		if !strings.Contains(reply, want) {
+			t.Fatalf("reply missing %q, got %q", want, reply)
+		}
 	}
 }
 

pkg/session/manager.go

@@ -51,6 +51,7 @@ type SessionMeta struct {
 	UpdatedAt  time.Time `json:"updated_at"`
 	MessageCnt int       `json:"message_cnt"`
 	Active     bool      `json:"active"`
+	Summary    string    `json:"summary,omitempty"`
 }
 
 type SessionManager struct {
@@ -740,6 +741,7 @@ func (sm *SessionManager) buildSessionMetaListLocked(scope *scopeIndex) []Sessio
 		if session, ok := sm.sessions[key]; ok {
 			meta.UpdatedAt = session.Updated
 			meta.MessageCnt = len(session.Messages)
+			meta.Summary = session.Summary
 		}
 		list = append(list, meta)
 	}