feat(intelligence): Phase 5 主动行为激活 — 注入格式 + 跨会话连续性 + 触发持久化

Task 5.1+5.4: ButlerRouter/experience 注入格式升级为 <butler-context> XML fencing
- butler_router: [路由上下文] → <butler-context><routing>...</routing></butler-context>
- experience: [过往经验] → <butler-context><experience>...</experience></butler-context>
- 统一 system-note 提示，引导 LLM 自然运用上下文

Task 5.2: 跨会话连续性 — pre_conversation_hook 注入活跃痛点 + 相关经验
- 从 VikingStorage 检索相关记忆(相似度>=0.3)
- 从 pain_aggregator 获取 High severity 痛点(top 3)

Task 5.3: 触发信号持久化 — post_conversation_hook 将触发信号存入 VikingStorage
- store_trigger_experience(): 模板提取，零 LLM 成本
- 为未来 LLM 深度反思积累数据基础

desktop/src-tauri/src/intelligence/experience.rs

@@ -204,6 +204,7 @@ impl ExperienceExtractor {
 
     /// Format experiences for system prompt injection.
     /// Returns a concise block capped at ~200 Chinese characters.
+    /// Uses `<butler-context>` XML fencing for structured injection.
     /// Includes industry context when available.
     pub fn format_for_injection(
         experiences: &[zclaw_growth::experience_store::Experience],
@@ -224,14 +225,14 @@ impl ExperienceExtractor {
                 .map(|s| truncate(s, 40))
                 .unwrap_or_default();
             let industry_tag = exp.industry_context.as_ref()
-                .map(|i| format!(", 行业:{}", i))
+                .map(|i| format!(" 行业:{}", i))
                 .unwrap_or_default();
             let line = format!(
-                "[过往经验{}] 类似「{}」做过：{}，结果是{}",
-                industry_tag,
+                "- 类似「{}」做过：{}，结果是{} ({})",
                 truncate(&exp.pain_pattern, 30),
                 step_summary,
-                exp.outcome
+                exp.outcome,
+                industry_tag.trim_start()
             );
             total_chars += line.chars().count();
             parts.push(line);
@@ -241,7 +242,10 @@ impl ExperienceExtractor {
             return String::new();
         }
 
-        format!("\n\n--- 过往经验参考 ---\n{}", parts.join("\n"))
+        format!(
+            "\n\n<butler-context>\n<experience>\n{}\n</experience>\n</butler-context>",
+            parts.join("\n")
+        )
     }
 }
 
@@ -345,7 +349,8 @@ mod tests {
             "成功解决",
         );
         let formatted = ExperienceExtractor::format_for_injection(&[exp]);
-        assert!(formatted.contains("过往经验"));
+        assert!(formatted.contains("butler-context"));
+        assert!(formatted.contains("experience"));
         assert!(formatted.contains("出口包装问题"));
     }