fix(memory): CJK-aware short query threshold + Chinese synonym expansion

1. MemoryMiddleware: replace byte-length check (query.len() < 4) with
   char-count check (query.chars().count() < 2). Single CJK characters
   are 3 UTF-8 bytes but 1 meaningful character — the old threshold
   incorrectly skipped 1-2 char Chinese queries like "你好".

2. QueryAnalyzer: add Chinese synonym mappings for 13 common technical
   terms (错误→bug, 优化→improve, 配置→config, etc.) so CJK queries
   can find relevant English-keyword memories and vice versa.

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

crates/zclaw-growth/src/retrieval/query.rs

@@ -216,9 +216,10 @@ impl QueryAnalyzer {
         expansions
     }
 
-    /// Get synonyms for a keyword (simplified)
+    /// Get synonyms for a keyword (simplified, English + Chinese)
     fn get_synonyms(&self, keyword: &str) -> Option<Vec<String>> {
         let synonyms: &[&str] = match keyword {
+            // English synonyms
             "code" => &["program", "script", "source"],
             "error" => &["bug", "issue", "problem", "exception"],
             "fix" => &["solve", "resolve", "repair", "patch"],
@@ -226,6 +227,20 @@ impl QueryAnalyzer {
             "slow" => &["performance", "optimize", "speed"],
             "help" => &["assist", "support", "guide", "aid"],
             "learn" => &["study", "understand", "know", "grasp"],
+            // Chinese synonyms — critical for Chinese-language queries
+            "错误" => &["问题", "bug", "异常", "故障"],
+            "修复" => &["解决", "修正", "处理", "fix"],
+            "优化" => &["改进", "提升", "加速", "improve"],
+            "配置" => &["设置", "参数", "选项", "config"],
+            "性能" => &["速度", "效率", "performance"],
+            "问题" => &["错误", "故障", "issue", "problem"],
+            "帮助" => &["协助", "支持", "help"],
+            "学习" => &["了解", "掌握", "learn"],
+            "代码" => &["程序", "脚本", "code"],
+            "数据库" => &["DB", "database", "存储"],
+            "部署" => &["发布", "上线", "deploy"],
+            "测试" => &["验证", "检验", "test"],
+            "安全" => &["防护", "加密", "security"],
             _ => return None,
         };