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.

agents/types.go

@@ -0,0 +1,20 @@
+package agents
+
+import (
+	"context"
+
+	"github.com/enmanuel/agents/pkg/command"
+)
+
+// Runner is the common interface that both Agent and Robot satisfy.
+// The launcher uses this to manage agents and robots uniformly.
+type Runner interface {
+	// Run starts the Matrix sync loop. Blocks until ctx is cancelled.
+	Run(ctx context.Context) error
+	// Stop cancels the runner's internal context, causing Run to return.
+	Stop()
+	// Done returns a channel closed when Run has returned.
+	Done() <-chan struct{}
+	// RegisterCommand adds a custom command handler.
+	RegisterCommand(spec command.Spec, handler CommandHandler)
+}