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/json_utils.rs

@@ -0,0 +1,63 @@
+//! 共享 JSON 工具函数
+//! 从 LLM 返回的文本中提取 JSON 块
+
+/// 从 LLM 返回文本中提取 JSON 块
+/// 支持三种格式：```json...``` 围栏、```...``` 围栏、裸 {...}
+pub fn extract_json_block(text: &str) -> &str {
+    // 尝试匹配 ```json ... ```
+    if let Some(start) = text.find("```json") {
+        let json_start = start + 7;
+        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()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_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\"}");
+    }
+
+    #[test]
+    fn test_json_block_bare() {
+        let text = "{\"key\": \"value\"}";
+        assert_eq!(extract_json_block(text), "{\"key\": \"value\"}");
+    }
+
+    #[test]
+    fn test_json_block_plain_fences() {
+        let text = "Result:\n```\n{\"a\": 1}\n```";
+        assert_eq!(extract_json_block(text), "{\"a\": 1}");
+    }
+
+    #[test]
+    fn test_json_block_nested_braces() {
+        let text = r#"{"outer": {"inner": "val"}}"#;
+        assert_eq!(extract_json_block(text), r#"{"outer": {"inner": "val"}}"#);
+    }
+
+    #[test]
+    fn test_json_block_no_json() {
+        let text = "no json here";
+        assert_eq!(extract_json_block(text), "no json here");
+    }
+}