fix(cli): show real MEMBERS count in multica squad list

The MEMBERS column was hardcoded to "-" in the table output, so every
squad looked empty even though the backend already returns
`member_count` (and `member_preview`) on each row. `squad get --output
json` exposed the correct data, which is why the bug was cosmetic but
confusing.

Read `member_count` from the response and render it; fall back to "-"
when missing or zero so empty squads stay visually distinct.

Fixes #3304 (MUL-2706).

Co-authored-by: multica-agent <github@multica.ai>

server/cmd/multica/cmd_squad.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strconv"
 	"text/tabwriter"
 	"time"
 
@@ -52,12 +53,25 @@ func runSquadList(cmd *cobra.Command, _ []string) error {
 	w := tabwriter.NewWriter(os.Stdout, 0, 4, 2, ' ', 0)
 	fmt.Fprintln(w, "ID\tNAME\tLEADER ID\tMEMBERS")
 	for _, s := range squads {
-		fmt.Fprintf(w, "%s\t%s\t%s\t-\n",
-			strVal(s, "id"), strVal(s, "name"), strVal(s, "leader_id"))
+		fmt.Fprintf(w, "%s\t%s\t%s\t%s\n",
+			strVal(s, "id"), strVal(s, "name"), strVal(s, "leader_id"),
+			memberCountDisplay(s))
 	}
 	return w.Flush()
 }
 
+func memberCountDisplay(m map[string]any) string {
+	v, ok := m["member_count"]
+	if !ok || v == nil {
+		return "-"
+	}
+	n, ok := v.(float64)
+	if !ok || n <= 0 {
+		return "-"
+	}
+	return strconv.Itoa(int(n))
+}
+
 // ── Get ─────────────────────────────────────────────────────────────────────
 
 var squadGetCmd = &cobra.Command{