Add a structured logger and collector so runs can be traced across processes.

Sync and async sinks, redaction, and a queryable HTTP service keep concurrent logs tied to a trace id.

Co-authored-by: Cursor <cursoragent@cursor.com>

logsys/format.go

@@ -0,0 +1,61 @@
+package logsys
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+)
+
+// FormatJSON 把条目编码为一行 JSON（含换行）。
+func FormatJSON(e Entry) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	enc.SetEscapeHTML(false)
+	if err := enc.Encode(e); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// FormatHuman 把条目格式化成单行文本（含换行）。
+func FormatHuman(e Entry) string {
+	ts := e.Time.UTC().Format(time.RFC3339Nano)
+	var b strings.Builder
+	fmt.Fprintf(&b, "%s %s", ts, strings.ToUpper(e.Level))
+	if e.Service != "" || e.Module != "" {
+		b.WriteByte(' ')
+		b.WriteString(e.Service)
+		if e.Module != "" {
+			if e.Service != "" {
+				b.WriteByte('/')
+			}
+			b.WriteString(e.Module)
+		}
+	}
+	b.WriteByte(' ')
+	b.WriteString(e.Message)
+	if e.Code != "" {
+		fmt.Fprintf(&b, " code=%s", e.Code)
+	}
+	if e.TraceID != "" {
+		fmt.Fprintf(&b, " trace=%s", e.TraceID)
+	}
+	if e.Error != "" {
+		fmt.Fprintf(&b, " error=%q", e.Error)
+	}
+	if len(e.Fields) > 0 {
+		keys := make([]string, 0, len(e.Fields))
+		for k := range e.Fields {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for _, k := range keys {
+			fmt.Fprintf(&b, " %s=%v", k, e.Fields[k])
+		}
+	}
+	b.WriteByte('\n')
+	return b.String()
+}