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/assistant-bot/agent.go

@@ -0,0 +1,30 @@
+// Package assistant defines the pure rules for the assistant bot.
+// Since this bot is primarily LLM-driven, most rules just route to the LLM.
+package assistant
+
+import (
+	"github.com/enmanuel/agents/agents"
+	"github.com/enmanuel/agents/pkg/decision"
+)
+
+func init() {
+	agents.Register("assistant-bot", Rules)
+}
+
+// Rules returns the decision rules for the assistant bot.
+// Note: !help is now handled by the built-in command system.
+func Rules() []decision.Rule {
+	return []decision.Rule{
+		// Any DM or mention → LLM
+		{
+			Name: "llm-all",
+			Match: func(ctx decision.MessageContext) bool {
+				return ctx.IsDirectMsg || ctx.IsMention
+			},
+			Actions: []decision.Action{{
+				Kind: decision.ActionKindLLM,
+				LLM:  &decision.LLMAction{},
+			}},
+		},
+	}
+}