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/logger/logger.go

@@ -0,0 +1,101 @@
+// Package logger provides structured JSONL logging for agents with daily
+// file rotation, size-based splitting, automatic cleanup, and query helpers.
+package logger
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"time"
+)
+
+// Standard field names for structured logging across all agents.
+const (
+	FieldAgentID    = "agent_id"
+	FieldTraceID    = "trace_id"
+	FieldAction     = "action"
+	FieldReason     = "reason"
+	FieldDurationMS = "duration_ms"
+	FieldTokensUsed = "tokens_used"
+	FieldResult     = "result"
+	FieldErrorType  = "error_type"
+	FieldComponent  = "component"
+)
+
+// traceKey is the context key for trace IDs.
+type traceKey struct{}
+
+// WithTraceID returns a new context carrying the given trace ID.
+func WithTraceID(ctx context.Context, id string) context.Context {
+	return context.WithValue(ctx, traceKey{}, id)
+}
+
+// TraceIDFromCtx extracts the trace ID from ctx, or "" if absent.
+func TraceIDFromCtx(ctx context.Context) string {
+	if v, ok := ctx.Value(traceKey{}).(string); ok {
+		return v
+	}
+	return ""
+}
+
+// LoggerConfig configures a per-agent logger.
+type LoggerConfig struct {
+	BaseDir         string        // root log directory (default: "logs"); empty → stdout only
+	AgentID         string        // agent identifier (required)
+	MaxSizeMB       int64         // max file size before rotation (default: 50)
+	MaxAgeDays      int           // retention in days (default: 7)
+	Compress        bool          // gzip rotated files (default: true)
+	CleanupInterval time.Duration // cleanup ticker interval (default: 24h)
+	Level           slog.Level    // minimum log level (default: INFO)
+}
+
+func (c *LoggerConfig) defaults() {
+	if c.BaseDir == "" {
+		c.BaseDir = "logs"
+	}
+	if c.MaxSizeMB <= 0 {
+		c.MaxSizeMB = 50
+	}
+	if c.MaxAgeDays <= 0 {
+		c.MaxAgeDays = 7
+	}
+	if c.CleanupInterval <= 0 {
+		c.CleanupInterval = 24 * time.Hour
+	}
+}
+
+// NewAgentLogger creates a structured JSON logger that writes to daily-rotated
+// JSONL files under BaseDir/<AgentID>/. It returns:
+//   - a *slog.Logger pre-enriched with agent_id
+//   - a cleanup func to call on shutdown (closes files, stops cleanup goroutine)
+//   - an error if the log directory cannot be created
+//
+// If BaseDir is literally "stdout", the logger writes to os.Stdout with no
+// file rotation or cleanup.
+func NewAgentLogger(cfg LoggerConfig) (*slog.Logger, func(), error) {
+	if cfg.BaseDir == "stdout" {
+		h := slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: cfg.Level})
+		l := slog.New(h).With(FieldAgentID, cfg.AgentID)
+		return l, func() {}, nil
+	}
+
+	cfg.defaults()
+
+	w, err := NewDailyRotatingWriter(cfg.BaseDir, cfg.AgentID, cfg.MaxSizeMB, cfg.Compress)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	h := slog.NewJSONHandler(w, &slog.HandlerOptions{Level: cfg.Level})
+	l := slog.New(h).With(FieldAgentID, cfg.AgentID)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	go runCleanup(ctx, cfg.BaseDir, cfg.AgentID, cfg.MaxAgeDays, cfg.CleanupInterval)
+
+	cleanup := func() {
+		cancel()
+		w.Close()
+	}
+
+	return l, cleanup, nil
+}