feat: integrar RBAC y allowlist de usuarios en runtime y listener

Cambios en 3 archivos:
- agents/runtime.go: construye ACL desde config de roles, verifica permisos
  antes de ejecutar comandos (command:<name>), interacción LLM (ask) y
  ejecución de tools (tool:<name>). Mensajes denegados se loguean y
  responden al usuario.
- shell/matrix/listener.go: filtra invites y mensajes de usuarios no
  autorizados cuando se configura allowed_users (allowlist vacía = todos).
- internal/config/schema.go: añade campos AllowedUsers y
  UnauthorizedResponse a FiltersCfg para soportar la allowlist en config.

Esto conecta el paquete pkg/acl con el runtime para dar soporte completo
a control de acceso por rol, sin romper la compatibilidad (ACL vacío
permite todo como antes).

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

agents/runtime.go

@@ -15,6 +15,7 @@ import (
 	"maunium.net/go/mautrix/event"
 
 	"github.com/enmanuel/agents/internal/config"
+	"github.com/enmanuel/agents/pkg/acl"
 	"github.com/enmanuel/agents/pkg/command"
 	"github.com/enmanuel/agents/pkg/decision"
 	coretypes "github.com/enmanuel/agents/pkg/llm"
@@ -60,6 +61,9 @@ type Agent struct {
 	logger      *slog.Logger
 	cryptoStore io.Closer // non-nil when E2EE is enabled; closed on shutdown
 
+	// Access control
+	acl acl.ACL
+
 	// Commands — handlers keyed by canonical name; cmdAliases maps alias → canonical
 	commands     map[string]CommandHandler
 	cmdAliases   map[string]string        // alias → canonical name
@@ -209,11 +213,22 @@ func New(cfg *config.AgentConfig, rules []decision.Rule, logger *slog.Logger) (*
 		}
 	}
 
+	// Build ACL from security roles config
+	aclRoles := make(map[string]acl.RoleDef, len(cfg.Security.Roles))
+	for name, r := range cfg.Security.Roles {
+		aclRoles[name] = acl.RoleDef{Users: r.Users, Actions: r.Actions}
+	}
+	agentACL := acl.FromMap(aclRoles)
+	if !agentACL.Empty() {
+		logger.Info("acl enabled", "roles", len(cfg.Security.Roles))
+	}
+
 	// Tool registry — register tools enabled in config
 	toolReg := buildToolRegistry(cfg, sshExec, matrixClient, memStore, kStore, roomCtx, logger)
 
 	a := &Agent{
 		cfg:         cfg,
+		acl:         agentACL,
 		rules:       rules,
 		llm:         llmFunc,
 		matrix:      matrixClient,
@@ -497,6 +512,13 @@ func (a *Agent) handleEvent(ctx context.Context, msgCtx decision.MessageContext,
 		}
 
 		if handler, ok := a.commands[cmdName]; ok {
+			// RBAC check for commands
+			if !a.acl.CanDo(msgCtx.SenderID, "command:"+cmdName) {
+				a.logger.Info("command_denied", "command", cmdName, "sender", msgCtx.SenderID)
+				_ = a.matrix.SendReplyMarkdown(ctx, roomID, msgCtx.EventID,
+					"No tienes permisos para ejecutar este comando.")
+				return
+			}
 			a.logger.Info("command_executed", "command", cmdName)
 			reply := handler(ctx, msgCtx)
 			_ = a.matrix.SendReplyMarkdown(ctx, roomID, msgCtx.EventID, reply)
@@ -520,6 +542,14 @@ func (a *Agent) handleEvent(ctx context.Context, msgCtx decision.MessageContext,
 	}
 
 	// ── Non-command flow ─────────────────────────────────────────────
+	// RBAC check for LLM access ("ask" action)
+	if !a.acl.CanDo(msgCtx.SenderID, "ask") {
+		a.logger.Info("ask_denied", "sender", msgCtx.SenderID)
+		_ = a.matrix.SendReplyMarkdown(ctx, roomID, msgCtx.EventID,
+			"No tienes permisos para interactuar con este agente.")
+		return
+	}
+
 	actions := decision.Evaluate(msgCtx, a.rules)
 	a.logger.Debug("rules evaluated", "matched_actions", len(actions))
 
@@ -667,6 +697,17 @@ func (a *Agent) runLLM(ctx context.Context, msgCtx decision.MessageContext) (str
 				"call_id", tc.ID,
 			)
 
+			// RBAC check for tool execution
+			if !a.acl.CanDo(msgCtx.SenderID, "tool:"+tc.Name) {
+				a.logger.Info("tool_denied", "tool", tc.Name, "sender", msgCtx.SenderID)
+				messages = append(messages, coretypes.Message{
+					Role:       coretypes.RoleTool,
+					Content:    "error: permission denied for tool " + tc.Name,
+					ToolCallID: tc.ID,
+				})
+				continue
+			}
+
 			// Notify the room that a tool is being called
 			toolNotice := fmt.Sprintf("🔨 <em>%s</em>", tc.Name)
 			if err := a.matrix.SendMarkdown(ctx, msgCtx.RoomID, toolNotice); err != nil {