feat: import agents_and_robots platform as unibots (Matrix-out, unibus transport)

Reemplaza el scaffold del echobot por la plataforma completa de bots traida
desde ~/DataProyects/Github/agents_and_robots tras la operacion Matrix-out:
los bots ya no hablan por Matrix sino por el bus unibus (modelo todo-rooms +
E2E via shell/transportunibus sobre github.com/enmanuel/unibus/pkg/client).

- go.mod: replace de unibus -> ../unibus y de fn-registry -> ../../../.. (paths
  relativos reajustados a la nueva ubicacion dentro de fn_registry).
- app.md: bump a 0.2.0, descripcion + arquitectura + comandos + gotchas reales.
- modulo Go conservado como github.com/enmanuel/agents (sin reescribir imports).

agents_and_robots queda archivado como museo de la era Matrix.

shell/cron/scheduler.go

@@ -0,0 +1,110 @@
+// Package cron provides a scheduler for autonomous bot activity.
+// It is part of the impure shell: it reads files, calls LLMs, and sends messages
+// over the bot's transport (unibus).
+package cron
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/robfig/cron/v3"
+
+	"github.com/enmanuel/agents/internal/config"
+	coretypes "github.com/enmanuel/agents/pkg/llm"
+)
+
+// Sender is the subset of the bot's transport sender needed by the scheduler.
+type Sender interface {
+	SendMarkdown(ctx context.Context, roomID, markdown string) error
+}
+
+// Scheduler fires configured schedules and executes send_message or llm_prompt actions.
+type Scheduler struct {
+	cfg    []config.ScheduleCfg
+	sender Sender
+	llm    coretypes.CompleteFunc // nil when agent has no LLM
+	model  string
+	logger *slog.Logger
+	cron   *cron.Cron
+}
+
+// New creates a Scheduler. llm and model are optional (nil/empty for agents without LLM).
+func New(
+	cfg []config.ScheduleCfg,
+	sender Sender,
+	llm coretypes.CompleteFunc,
+	model string,
+	logger *slog.Logger,
+) *Scheduler {
+	return &Scheduler{
+		cfg:    cfg,
+		sender: sender,
+		llm:    llm,
+		model:  model,
+		logger: logger.With("component", "cron"),
+		cron:   cron.New(),
+	}
+}
+
+// Fire immediately executes the action for the given schedule, bypassing the cron timer.
+// Useful for tests and manual triggering from CLI.
+func (s *Scheduler) Fire(ctx context.Context, sc config.ScheduleCfg) {
+	room := sc.OutputRoom
+	if room == "" {
+		s.logger.Warn("Fire: schedule has no output_room, skipping", "name", sc.Name)
+		return
+	}
+	handler := s.buildHandler(sc)
+	if handler == nil {
+		s.logger.Warn("Fire: unsupported action kind", "name", sc.Name, "kind", sc.Action.Kind)
+		return
+	}
+	handler(ctx, room)
+}
+
+// Start registers all schedules and starts the cron loop.
+// It returns when ctx is cancelled, stopping the cron runner.
+func (s *Scheduler) Start(ctx context.Context) {
+	for _, sc := range s.cfg {
+		sc := sc // capture range var
+		if sc.Cron == "" || sc.Action.Kind == "" {
+			s.logger.Warn("skipping invalid schedule", "name", sc.Name, "cron", sc.Cron, "kind", sc.Action.Kind)
+			continue
+		}
+
+		room := sc.OutputRoom
+		if room == "" {
+			s.logger.Warn("schedule has no output_room, skipping", "name", sc.Name)
+			continue
+		}
+
+		handler := s.buildHandler(sc)
+		if handler == nil {
+			s.logger.Warn("unsupported action kind, skipping", "name", sc.Name, "kind", sc.Action.Kind)
+			continue
+		}
+
+		_, err := s.cron.AddFunc(sc.Cron, func() {
+			handler(ctx, room)
+		})
+		if err != nil {
+			s.logger.Error("failed to register schedule",
+				"name", sc.Name,
+				"cron", sc.Cron,
+				"err", err,
+			)
+			continue
+		}
+
+		s.logger.Info("schedule registered", "name", sc.Name, "cron", sc.Cron, "kind", sc.Action.Kind, "room", room)
+	}
+
+	s.cron.Start()
+	s.logger.Info("cron scheduler started", "schedules", len(s.cfg))
+
+	<-ctx.Done()
+	s.logger.Info("cron scheduler stopping")
+	cronCtx := s.cron.Stop()
+	<-cronCtx.Done()
+	s.logger.Info("cron scheduler stopped")
+}