fix(growth): 审计修复 — CRITICAL 编译错误 + LOW 静默数据丢失

- CRITICAL: extraction_adapter.rs extract_with_prompt() 使用不存在的
  zclaw_types::Error::msg()，改为 ZclawError::InvalidInput/ZclawError::LlmError
- LOW: feedback_collector.rs save() 中 serde_json::to_string().unwrap_or_default()
  改为显式错误处理 + warn 日志 + continue，避免静默存空数据

crates/zclaw-growth/src/feedback_collector.rs

@@ -135,8 +135,17 @@ impl FeedbackCollector {
 
         let mut saved = 0;
         for record in self.trust_records.values() {
-            let content =
-                serde_json::to_string(record).unwrap_or_default();
+            let content = match serde_json::to_string(record) {
+                Ok(c) => c,
+                Err(e) => {
+                    tracing::warn!(
+                        "[FeedbackCollector] Failed to serialize trust record {}: {}",
+                        record.artifact_id,
+                        e
+                    );
+                    continue;
+                }
+            };
             let entry = crate::types::MemoryEntry::new(
                 "feedback",
                 MemoryType::Session,