fix(log): input text visibility + space-in-date 502

- UnifiedQueryPanel: fix JS operator precedence — .replace(' ','T') was
  called on '.000Z' suffix instead of concatenated string, resulting in
  '2026-06-27 12:46:28.000Z' (space not replaced) → ES 502
- normalizeTime: add space→T fallback for backward compat
- SyntaxHighlightInput: fix z-index layering (textarea z=2 was covering
  pre z=1, making highlighted text invisible). Move bg/border to parent,
  textarea bg→transparent, pre above textarea

.gitignore

@@ -91,3 +91,4 @@ backend/cmd/static/
 # kubectl 二进制（预打包进镜像，避免 Docker build 时网络下载）
 backend/kubectl
 opsxsql/
+test_monitoring_es.py