[BUG] — `LoggingServerHttpResponse`: `new KeyWordMatch(...)` per response across ALL async-logging plugins

- severity: Medium
- files: `shenyu-plugin-logging/shenyu-plugin-logging-common/.../body/LoggingServerHttpResponse.java:97` (constructor builds `KeyWordMatch` → `Pattern.compile`), constructed in `AbstractLoggingPlugin.doExecute` (kafka/rocketmq/pulsar/rabbitmq/clickhouse/elasticsearch/huawei-lts)
- description: A fresh `KeyWordMatch` is built for every response whenever desensitization keywords are configured, across all async-logging plugins.
- impact: Per-response regex compile across the entire logging-plugin family.
- suggested_fix: Build the `KeyWordMatch` once per rule-handle and reuse; pass the compiled matcher into the response decorator.
- confidence: High

---
_Identified during the 2026-08-02 deep re-scan; full list in [`docs/scan2-2026-08-02/06-medium-tiers.md`](docs/scan2-2026-08-02/06-medium-tiers.md)._

Start with shenyu-plugin-logging/shenyu-plugin-logging-common/.../body/LoggingServerHttpResponse.java:97 and trace construction from AbstractLoggingPlugin.doExecute across the Kafka, RocketMQ, Pulsar, RabbitMQ, ClickHouse, Elasticsearch, and Huawei LTS plugins. Confirm how each rule handle creates the response decorator. Done means one compiled KeyWordMatch is reused per rule handle instead of compiling a pattern for every response.

Written by the indexing model from the issue text.