test: tests para comandos sin prefijo

Tests del parser (pkg/message/parse_test.go):
- Con prefijo !: comando estandar, con args, sin prefijo no detecta, lowercase
- Sin prefijo: comando bare, con args, ! retrocompatible, primer token, lowercase
- Casos borde: mensaje vacio, solo espacios, solo "!"
- Retrocompatibilidad: "!help" con prefix="" produce mismo resultado que con "!"
- Deteccion de menciones independiente del modo de prefijo

Tests del robot (agents/robot_test.go):
- !help muestra comandos sin ! cuando command_prefix es ""
- Comandos custom en modo sin prefijo
- Mismo conjunto de built-ins en ambos modos
- newTestRobot ahora configura command_prefix: "!" explicitamente

agents/robot_test.go

@@ -14,8 +14,20 @@ import (
 )
 
 // newTestRobot creates a minimal Robot for testing without requiring
-// Matrix or network. Fields are initialized directly.
+// Matrix or network. Fields are initialized directly. Uses standard "!" prefix.
 func newTestRobot(t *testing.T) *Robot {
+	t.Helper()
+	return newTestRobotWithPrefix(t, "!")
+}
+
+// newTestRobotNoPrefix creates a minimal Robot with command_prefix: "" (no prefix).
+func newTestRobotNoPrefix(t *testing.T) *Robot {
+	t.Helper()
+	return newTestRobotWithPrefix(t, "")
+}
+
+// newTestRobotWithPrefix creates a Robot with the given command prefix.
+func newTestRobotWithPrefix(t *testing.T, prefix string) *Robot {
 	t.Helper()
 	cfg := &config.AgentConfig{
 		Agent: config.AgentMeta{
@@ -25,6 +37,11 @@ func newTestRobot(t *testing.T) *Robot {
 			Description: "robot for tests",
 			Version:     "1.0.0",
 		},
+		Matrix: config.MatrixCfg{
+			Filters: config.FiltersCfg{
+				CommandPrefix: prefix,
+			},
+		},
 	}
 	r := &Robot{
 		cfg:        cfg,
@@ -288,3 +305,66 @@ func TestRobotBuiltinCommandCount(t *testing.T) {
 		}
 	}
 }
+
+// ── No-prefix command tests ───────────────────────────────────────────────
+
+// TestRobotNoPrefixCmdHelp verifies that help shows commands without ! prefix
+// when command_prefix is "".
+func TestRobotNoPrefixCmdHelp(t *testing.T) {
+	r := newTestRobotNoPrefix(t)
+
+	reply := r.cmdHelp(context.Background(), decision.MessageContext{})
+
+	if !strings.Contains(reply, "Comandos disponibles") {
+		t.Error("help reply missing header")
+	}
+
+	// Commands should appear WITHOUT ! prefix
+	for _, cmd := range []string{"help", "ping", "status", "info", "version"} {
+		// Should contain the command name
+		if !strings.Contains(reply, cmd) {
+			t.Errorf("help reply missing command %s", cmd)
+		}
+		// Should NOT contain "!cmd" as usage (but might contain it elsewhere)
+		if strings.Contains(reply, "!"+cmd) {
+			t.Errorf("help reply should not show !%s in no-prefix mode", cmd)
+		}
+	}
+}
+
+// TestRobotNoPrefixCmdHelpWithCustom verifies custom commands in no-prefix mode.
+func TestRobotNoPrefixCmdHelpWithCustom(t *testing.T) {
+	r := newTestRobotNoPrefix(t)
+
+	r.RegisterCommand(
+		command.Spec{Name: "deploy", Description: "Deploy to env", Usage: "deploy <env>"},
+		func(_ context.Context, _ decision.MessageContext) string { return "deployed" },
+	)
+
+	reply := r.cmdHelp(context.Background(), decision.MessageContext{})
+
+	if !strings.Contains(reply, "Comandos del robot") {
+		t.Error("help reply missing 'Comandos del robot' section")
+	}
+	if !strings.Contains(reply, "deploy") {
+		t.Error("help reply missing custom command deploy")
+	}
+}
+
+// TestRobotNoPrefixSameBuiltins verifies that no-prefix robots have the
+// same set of built-in commands as standard robots.
+func TestRobotNoPrefixSameBuiltins(t *testing.T) {
+	standard := newTestRobot(t)
+	noPrefix := newTestRobotNoPrefix(t)
+
+	if len(standard.commands) != len(noPrefix.commands) {
+		t.Errorf("command count mismatch: standard=%d, noPrefix=%d",
+			len(standard.commands), len(noPrefix.commands))
+	}
+
+	for name := range standard.commands {
+		if _, ok := noPrefix.commands[name]; !ok {
+			t.Errorf("no-prefix robot missing command %q", name)
+		}
+	}
+}