feat: integrar structured logging en todos los componentes del shell

Se propaga *slog.Logger a todos los componentes impuros del shell:
- shell/bus/ — logs de subscribe, send, reply, timeout, unsubscribe
- shell/effects/ — duración y resultado de cada action ejecutada
- shell/llm/ (anthropic, openai, factory) — request/response con tokens, duración, fallback
- shell/memory/sqlite — open, save, recall, close con detalles
- shell/ssh/ — inicio, fin, errores y duración de comandos SSH
- tools/registry — registro, ejecución y errores de herramientas

Se usa el paquete shell/logger para field names consistentes (FieldDurationMS, FieldTokensUsed, etc.).
Cada componente recibe el logger por inyección de dependencias, sin globals.
Las firmas de New/FromConfig se actualizan para aceptar *slog.Logger.

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

shell/llm/factory.go

@@ -3,24 +3,26 @@ package llm
 import (
 	"context"
 	"fmt"
+	"log/slog"
 
 	"github.com/enmanuel/agents/internal/config"
 	coretypes "github.com/enmanuel/agents/pkg/llm"
 )
 
 // FromConfig builds a CompleteFunc from an LLMProviderCfg.
-func FromConfig(cfg config.LLMProviderCfg) (coretypes.CompleteFunc, error) {
+func FromConfig(cfg config.LLMProviderCfg, log *slog.Logger) (coretypes.CompleteFunc, error) {
+	log.Info("llm_provider_init", "provider", cfg.Provider, "model", cfg.Model)
 	switch cfg.Provider {
 	case "anthropic":
-		return NewAnthropicComplete(cfg.APIKeyEnv, cfg.BaseURL), nil
+		return NewAnthropicComplete(cfg.APIKeyEnv, cfg.BaseURL, log), nil
 	case "openai":
-		return NewOpenAIComplete(cfg.APIKeyEnv, cfg.BaseURL), nil
+		return NewOpenAIComplete(cfg.APIKeyEnv, cfg.BaseURL, log), nil
 	case "ollama":
 		base := cfg.BaseURL
 		if base == "" {
 			base = "http://localhost:11434/v1"
 		}
-		return NewOpenAIComplete("OLLAMA_API_KEY", base), nil
+		return NewOpenAIComplete("OLLAMA_API_KEY", base, log), nil
 	default:
 		return nil, fmt.Errorf("unknown LLM provider: %s", cfg.Provider)
 	}
@@ -28,10 +30,11 @@ func FromConfig(cfg config.LLMProviderCfg) (coretypes.CompleteFunc, error) {
 
 // WithFallback wraps primary with a fallback CompleteFunc.
 // If primary returns an error, fallback is tried.
-func WithFallback(primary, fallback coretypes.CompleteFunc) coretypes.CompleteFunc {
+func WithFallback(primary, fallback coretypes.CompleteFunc, log *slog.Logger) coretypes.CompleteFunc {
 	return func(ctx context.Context, req coretypes.CompletionRequest) (coretypes.CompletionResponse, error) {
 		resp, err := primary(ctx, req)
 		if err != nil {
+			log.Warn("llm_fallback_triggered", "primary_err", err)
 			return fallback(ctx, req)
 		}
 		return resp, nil