feat: permitir comandos de robots sin prefijo !

Cuando command_prefix es "" en el config, el parser trata el primer token
del mensaje como nombre de comando sin requerir el prefijo !. Si el token
empieza con !, se le quita igualmente para retrocompatibilidad.

Cambios:
- pkg/message/parse.go: modo sin prefijo en Parse() (puro, sin side effects)
- agents/robot.go: mensaje "comando desconocido" y !help adaptados al prefijo
- agents/handler.go: mensaje "comando desconocido" adaptado al prefijo
- internal/config/schema.go: documentar command_prefix: "" en FiltersCfg
- agents/_template_robot/config.yaml: ejemplo comentado de command_prefix: ""

El comportamiento con command_prefix: "!" no cambia (retrocompatible).

agents/_template_robot/config.yaml

@@ -44,7 +44,8 @@ matrix:
     admin: []
 
   filters:
-    command_prefix: "!"
+    command_prefix: "!"         # usar "" para permitir comandos sin prefijo !
+    # command_prefix: ""        # sin prefijo: todo mensaje es un posible comando
     mention_respond: false      # robots no responden a menciones (no hay LLM)
     dm_respond: false           # robots no responden a DMs (no hay LLM)
     ignore_bots: true

agents/handler.go

@@ -74,8 +74,11 @@ func (a *Agent) handleEvent(ctx context.Context, msgCtx decision.MessageContext,
 		} else {
 			// Unknown command — never falls through to rules or LLM
 			a.logger.Info("command_unknown", "command", msgCtx.Command)
-			_ = a.sendReply(ctx, roomID, msgCtx.EventID, msgCtx.ThreadID,
-				fmt.Sprintf("Comando desconocido: `!%s`. Usa `!help` para ver comandos disponibles.", msgCtx.Command))
+			unknownMsg := fmt.Sprintf("Comando desconocido: `!%s`. Usa `!help` para ver comandos disponibles.", msgCtx.Command)
+			if a.cfg.Matrix.Filters.CommandPrefix == "" {
+				unknownMsg = fmt.Sprintf("Comando desconocido: `%s`. Usa `help` para ver comandos disponibles.", msgCtx.Command)
+			}
+			_ = a.sendReply(ctx, roomID, msgCtx.EventID, msgCtx.ThreadID, unknownMsg)
 			return
 		}
 	}

agents/robot.go

@@ -206,8 +206,11 @@ func (r *Robot) handleEvent(ctx context.Context, msgCtx decision.MessageContext,
 
 	// Unknown command
 	r.logger.Info("command_unknown", "command", msgCtx.Command)
-	_ = r.sendReply(ctx, roomID, msgCtx.EventID, msgCtx.ThreadID,
-		fmt.Sprintf("Comando desconocido: `!%s`. Usa `!help` para ver comandos disponibles.", msgCtx.Command))
+	unknownMsg := fmt.Sprintf("Comando desconocido: `!%s`. Usa `!help` para ver comandos disponibles.", msgCtx.Command)
+	if r.cfg.Matrix.Filters.CommandPrefix == "" {
+		unknownMsg = fmt.Sprintf("Comando desconocido: `%s`. Usa `help` para ver comandos disponibles.", msgCtx.Command)
+	}
+	_ = r.sendReply(ctx, roomID, msgCtx.EventID, msgCtx.ThreadID, unknownMsg)
 }
 
 // sendReply sends a markdown reply that respects thread context.
@@ -224,13 +227,15 @@ func (r *Robot) cmdHelp(_ context.Context, _ decision.MessageContext) string {
 	var b strings.Builder
 	b.WriteString("**Comandos disponibles:**\n\n")
 
+	prefix := r.cfg.Matrix.Filters.CommandPrefix // "!" or ""
+
 	// Built-in commands appropriate for robots
 	robotBuiltins := []command.Spec{
-		{Name: "help", Aliases: []string{"h"}, Description: "Lista comandos disponibles", Usage: "!help"},
-		{Name: "ping", Description: "Alive check", Usage: "!ping"},
-		{Name: "status", Description: "Info del robot: uptime", Usage: "!status"},
-		{Name: "info", Description: "Nombre, version y descripcion", Usage: "!info"},
-		{Name: "version", Aliases: []string{"v"}, Description: "Version del robot", Usage: "!version"},
+		{Name: "help", Aliases: []string{"h"}, Description: "Lista comandos disponibles", Usage: prefix + "help"},
+		{Name: "ping", Description: "Alive check", Usage: prefix + "ping"},
+		{Name: "status", Description: "Info del robot: uptime", Usage: prefix + "status"},
+		{Name: "info", Description: "Nombre, version y descripcion", Usage: prefix + "info"},
+		{Name: "version", Aliases: []string{"v"}, Description: "Version del robot", Usage: prefix + "version"},
 	}
 	for _, spec := range robotBuiltins {
 		writeSpec(&b, spec)

internal/config/schema.go

@@ -263,6 +263,10 @@ type RoomsCfg struct {
 }
 
 type FiltersCfg struct {
+	// CommandPrefix is the prefix required for commands (e.g. "!" means "!help").
+	// Set to "" (empty) to allow commands without prefix — useful for robots where
+	// every message is a potential command. When empty, "!help" still works for
+	// backward compatibility (the leading "!" is stripped automatically).
 	CommandPrefix        string   `yaml:"command_prefix"`
 	MentionRespond       bool     `yaml:"mention_respond"`
 	DMRespond            bool     `yaml:"dm_respond"`

pkg/message/parse.go

@@ -38,12 +38,33 @@ func Parse(body, senderID, roomID string, powerLevel int, isDM bool, opts ParseO
 		}
 	}
 
-	// Parse command
-	if opts.CommandPrefix != "" && strings.HasPrefix(body, opts.CommandPrefix) {
-		parts := strings.Fields(strings.TrimPrefix(body, opts.CommandPrefix))
+	// Parse command.
+	// When CommandPrefix is non-empty (e.g. "!"), only messages starting with that
+	// prefix are treated as commands.
+	// When CommandPrefix is empty, every message is a potential command: the first
+	// token is the command name. If it starts with "!", the "!" is stripped for
+	// backward compatibility (so both "help" and "!help" work the same).
+	switch {
+	case opts.CommandPrefix != "":
+		// Standard mode: require prefix
+		if strings.HasPrefix(body, opts.CommandPrefix) {
+			parts := strings.Fields(strings.TrimPrefix(body, opts.CommandPrefix))
+			if len(parts) > 0 {
+				ctx.Command = strings.ToLower(parts[0])
+				ctx.Args = parts[1:]
+			}
+		}
+	case opts.CommandPrefix == "":
+		// No-prefix mode: treat first token as command
+		parts := strings.Fields(body)
 		if len(parts) > 0 {
-			ctx.Command = strings.ToLower(parts[0])
-			ctx.Args = parts[1:]
+			cmd := parts[0]
+			// Strip leading "!" for backward compatibility
+			cmd = strings.TrimPrefix(cmd, "!")
+			if cmd != "" {
+				ctx.Command = strings.ToLower(cmd)
+				ctx.Args = parts[1:]
+			}
 		}
 	}