feat: add structured JSONL logging package with rotation and query

Nuevo paquete shell/logger/ que implementa logging estructurado JSONL
para agentes. Incluye DailyRotatingWriter con rotación diaria y por
tamaño (50MB default), limpieza automática de archivos viejos (7 días),
compresión gzip de logs rotados, y funciones de consulta (ReadLogs,
SearchLogs, ListAgents, ListDates) para que agentes LLM puedan leer
logs de otros agentes. Basado en log/slog de stdlib, sin dependencias
externas. 18 tests unitarios cubren rotación, concurrencia y consultas.

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

shell/logger/query_test.go

@@ -0,0 +1,130 @@
+package logger
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func setupQueryDir(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+
+	bot1 := filepath.Join(dir, "bot1")
+	bot2 := filepath.Join(dir, "bot2")
+	os.MkdirAll(bot1, 0o755)
+	os.MkdirAll(bot2, 0o755)
+
+	lines := []string{
+		`{"time":"2026-03-05T10:00:00Z","level":"INFO","msg":"hello","action":"greet"}`,
+		`{"time":"2026-03-05T11:00:00Z","level":"ERROR","msg":"oops","action":"fail"}`,
+	}
+	os.WriteFile(filepath.Join(bot1, "2026-03-05.jsonl"),
+		[]byte(lines[0]+"\n"+lines[1]+"\n"), 0o644)
+	os.WriteFile(filepath.Join(bot1, "2026-03-06.jsonl"),
+		[]byte(`{"time":"2026-03-06T09:00:00Z","level":"INFO","msg":"day2"}`+"\n"), 0o644)
+
+	os.WriteFile(filepath.Join(bot2, "2026-03-06.jsonl"),
+		[]byte(`{"time":"2026-03-06T08:00:00Z","level":"DEBUG","msg":"bot2 log"}`+"\n"), 0o644)
+
+	return dir
+}
+
+func TestListAgents(t *testing.T) {
+	dir := setupQueryDir(t)
+	agents, err := ListAgents(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(agents) != 2 {
+		t.Fatalf("expected 2 agents, got %d", len(agents))
+	}
+	if agents[0] != "bot1" || agents[1] != "bot2" {
+		t.Errorf("agents = %v, want [bot1 bot2]", agents)
+	}
+}
+
+func TestListDates(t *testing.T) {
+	dir := setupQueryDir(t)
+	dates, err := ListDates(dir, "bot1")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(dates) != 2 {
+		t.Fatalf("expected 2 dates, got %d", len(dates))
+	}
+	if dates[0].Format("2006-01-02") != "2026-03-05" {
+		t.Errorf("first date = %v, want 2026-03-05", dates[0])
+	}
+}
+
+func TestReadDayLogs(t *testing.T) {
+	dir := setupQueryDir(t)
+	day := time.Date(2026, 3, 5, 0, 0, 0, 0, time.UTC)
+	entries, err := ReadDayLogs(dir, "bot1", day)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(entries) != 2 {
+		t.Fatalf("expected 2 entries, got %d", len(entries))
+	}
+}
+
+func TestReadLogs(t *testing.T) {
+	dir := setupQueryDir(t)
+	from := time.Date(2026, 3, 5, 0, 0, 0, 0, time.UTC)
+	to := time.Date(2026, 3, 6, 0, 0, 0, 0, time.UTC)
+	entries, err := ReadLogs(dir, "bot1", from, to)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(entries) != 3 {
+		t.Fatalf("expected 3 entries across 2 days, got %d", len(entries))
+	}
+}
+
+func TestSearchLogs(t *testing.T) {
+	dir := setupQueryDir(t)
+	from := time.Date(2026, 3, 5, 0, 0, 0, 0, time.UTC)
+	to := time.Date(2026, 3, 5, 0, 0, 0, 0, time.UTC)
+
+	results, err := SearchLogs(dir, "bot1", "action", "fail", from, to)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(results) != 1 {
+		t.Fatalf("expected 1 match, got %d", len(results))
+	}
+	var m map[string]any
+	json.Unmarshal(results[0], &m)
+	if m["msg"] != "oops" {
+		t.Errorf("msg = %v, want oops", m["msg"])
+	}
+}
+
+func TestSearchLogs_NoMatch(t *testing.T) {
+	dir := setupQueryDir(t)
+	from := time.Date(2026, 3, 5, 0, 0, 0, 0, time.UTC)
+	to := time.Date(2026, 3, 6, 0, 0, 0, 0, time.UTC)
+
+	results, err := SearchLogs(dir, "bot1", "action", "nonexistent", from, to)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(results) != 0 {
+		t.Errorf("expected 0 matches, got %d", len(results))
+	}
+}
+
+func TestListAgents_EmptyDir(t *testing.T) {
+	dir := t.TempDir()
+	agents, err := ListAgents(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(agents) != 0 {
+		t.Errorf("expected 0 agents, got %d", len(agents))
+	}
+}