fix(growth): Evolution Engine 穷尽审计 3CRITICAL + 3HIGH 全部修复

C-01: ExperienceExtractor 接入 ExperienceStore
- GrowthIntegration.new() 创建 ExperienceExtractor 时注入 ExperienceStore
- 经验持久化路径打通：extract_combined → persist_experiences → ExperienceStore

C-02+C-03: 进化触发链路全链路接通
- create_middleware_chain() 注册 EvolutionMiddleware (priority 78)
- MemoryMiddleware 持有 Arc<EvolutionMiddleware> 共享引用
- after_completion 中调用 check_evolution() → 推送 PendingEvolution
- EvolutionMiddleware 在下次对话前注入进化建议到 system prompt

H-01: FeedbackCollector loaded 标志修复
- load() 失败时保留 loaded=false，下次 save 重试
- 日志级别 debug → warn

H-03: FeedbackCollector 内部可变性
- EvolutionEngine.feedback 改为 Arc<Mutex<FeedbackCollector>>
- submit_feedback() 从 &mut self → &self，支持中间件 &self 调用路径
- GrowthIntegration.initialize() 从 &mut self → &self

H-05: 删除空测试 test_parse_empty_response (无 assert)

H-06: infer_experiences_from_memories() fallback
- Outcome::Success → Outcome::Partial (反映推断不确定性)

crates/zclaw-growth/src/feedback_collector.rs

@@ -137,13 +137,18 @@ impl FeedbackCollector {
     pub async fn save(&mut self) -> Result<usize, String> {
         // 首次保存前自动加载已有记录，防止丢失历史数据
         if !self.loaded {
-            if let Err(e) = self.load().await {
-                tracing::debug!(
-                    "[FeedbackCollector] Auto-load before save failed (non-fatal): {}",
-                    e
-                );
+            match self.load().await {
+                Ok(_) => {
+                    self.loaded = true;
+                }
+                Err(e) => {
+                    // 加载失败时保留 loaded=false，下次 save 会重试
+                    tracing::warn!(
+                        "[FeedbackCollector] Auto-load before save failed, will retry next save: {}",
+                        e
+                    );
+                }
             }
-            self.loaded = true;
         }
 
         let viking = match &self.viking {