feat: add millisecond-precision timestamps to all log entries (#91)

- Add timestamp prefix format [YYYY-MM-DD HH:MM:SS.mmm] to every log entry
- Resolves issue where logs lacked time information, making it impossible to determine when events (like "Unknown event format" errors) occurred
- Update tests to handle new timestamp format by stripping prefixes during validation
- All 27+ tests pass with new format

Implementation:
- Modified logger.go:369-370 to inject timestamp before message
- Updated concurrent_stress_test.go to strip timestamps for format checks

Fixes #81

Generated with SWE-Agent.ai

Co-authored-by: SWE-Agent.ai <noreply@swe-agent.ai>

codeagent-wrapper/concurrent_stress_test.go

@@ -13,6 +13,16 @@ import (
 	"time"
 )
 
+func stripTimestampPrefix(line string) string {
+	if !strings.HasPrefix(line, "[") {
+		return line
+	}
+	if idx := strings.Index(line, "] "); idx >= 0 {
+		return line[idx+2:]
+	}
+	return line
+}
+
 // TestConcurrentStressLogger 高并发压力测试
 func TestConcurrentStressLogger(t *testing.T) {
 	if testing.Short() {
@@ -79,7 +89,8 @@ func TestConcurrentStressLogger(t *testing.T) {
 	// 验证日志格式（纯文本，无前缀）
 	formatRE := regexp.MustCompile(`^goroutine-\d+-msg-\d+$`)
 	for i, line := range lines[:min(10, len(lines))] {
-		if !formatRE.MatchString(line) {
+		msg := stripTimestampPrefix(line)
+		if !formatRE.MatchString(msg) {
 			t.Errorf("line %d has invalid format: %s", i, line)
 		}
 	}
@@ -291,7 +302,7 @@ func TestLoggerOrderPreservation(t *testing.T) {
 	sequences := make(map[int][]int) // goroutine ID -> sequence numbers
 
 	for scanner.Scan() {
-		line := scanner.Text()
+		line := stripTimestampPrefix(scanner.Text())
 		var gid, seq int
 		// Parse format: G0-SEQ0001 (without INFO: prefix)
 		_, err := fmt.Sscanf(line, "G%d-SEQ%04d", &gid, &seq)

codeagent-wrapper/logger.go

@@ -366,7 +366,8 @@ func (l *Logger) run() {
 	defer ticker.Stop()
 
 	writeEntry := func(entry logEntry) {
-		fmt.Fprintf(l.writer, "%s\n", entry.msg)
+		timestamp := time.Now().Format("2006-01-02 15:04:05.000")
+		fmt.Fprintf(l.writer, "[%s] %s\n", timestamp, entry.msg)
 
 		// Cache error/warn entries in memory for fast extraction
 		if entry.isError {