fix(growth): Evolution Engine 审计修复 — 7项全部完成

HIGH-1: 提取共享 json_utils.rs，skill_generator/workflow_composer 去重
HIGH-2: FeedbackCollector Vec→HashMap，消除 unwrap() panic 风险
HIGH-3: ProfileUpdater 改为 collect_updates() 返回字段列表，
        growth.rs 直接 async 调用 update_field()，不再用 no-op 闭包
MEDIUM-1: EvolutionMiddleware 注入后自动 drain，防止重复注入
MEDIUM-2: PatternAggregator tools 提取改为直接收集 context 值
MEDIUM-3: evolution_engine.rs 移除 4 个未使用 imports
MEDIUM-4: workflow_composer parse_response pattern 参数加下划线
MEDIUM-7: SkillCandidate 添加 version 字段（默认=1）

测试: zclaw-growth 128 tests, zclaw-runtime 86 tests, workspace 0 failures

crates/zclaw-growth/src/skill_generator.rs

@@ -15,6 +15,8 @@ pub struct SkillCandidate {
     pub body_markdown: String,
     pub source_pattern: String,
     pub confidence: f32,
+    /// 技能版本号，用于后续迭代追踪
+    pub version: u32,
 }
 
 /// LLM 驱动的技能生成 prompt
@@ -59,8 +61,7 @@ impl SkillGenerator {
 
     /// 解析 LLM 返回的 JSON 为 SkillCandidate
     pub fn parse_response(json_str: &str, pattern: &AggregatedPattern) -> Result<SkillCandidate> {
-        // 尝试提取 JSON 块（LLM 可能包裹在 ```json ... ``` 中）
-        let json_str = extract_json_block(json_str);
+        let json_str = crate::json_utils::extract_json_block(json_str);
 
         let raw: serde_json::Value = serde_json::from_str(&json_str).map_err(|e| {
             zclaw_types::ZclawError::ConfigError(format!("Invalid skill JSON: {}", e))
@@ -95,35 +96,11 @@ impl SkillGenerator {
             body_markdown: raw["body_markdown"].as_str().unwrap_or("").to_string(),
             source_pattern: pattern.pain_pattern.clone(),
             confidence: raw["confidence"].as_f64().unwrap_or(0.5) as f32,
+            version: raw["version"].as_u64().unwrap_or(1) as u32,
         })
     }
 }
 
-/// 从 LLM 返回文本中提取 JSON 块
-fn extract_json_block(text: &str) -> &str {
-    // 尝试匹配 ```json ... ```
-    if let Some(start) = text.find("```json") {
-        let json_start = start + 7; // skip ```json
-        if let Some(end) = text[json_start..].find("```") {
-            return text[json_start..json_start + end].trim();
-        }
-    }
-    // 尝试匹配 ``` ... ```
-    if let Some(start) = text.find("```") {
-        let json_start = start + 3;
-        if let Some(end) = text[json_start..].find("```") {
-            return text[json_start..json_start + end].trim();
-        }
-    }
-    // 尝试找 { ... } 块
-    if let Some(start) = text.find('{') {
-        if let Some(end) = text.rfind('}') {
-            return &text[start..=end];
-        }
-    }
-    text.trim()
-}
-
 impl Default for SkillGenerator {
     fn default() -> Self {
         Self::new()
@@ -194,12 +171,12 @@ mod tests {
     #[test]
     fn test_extract_json_block_with_markdown() {
         let text = "Here is the result:\n```json\n{\"key\": \"value\"}\n```\nDone.";
-        assert_eq!(extract_json_block(text), "{\"key\": \"value\"}");
+        assert_eq!(crate::json_utils::extract_json_block(text), "{\"key\": \"value\"}");
     }
 
     #[test]
     fn test_extract_json_block_bare() {
         let text = "{\"key\": \"value\"}";
-        assert_eq!(extract_json_block(text), "{\"key\": \"value\"}");
+        assert_eq!(crate::json_utils::extract_json_block(text), "{\"key\": \"value\"}");
     }
 }