feat: 全链路优化 — 死锁修复、MD3主题、上下文持久化、群聊自然化、打字状态、知识库

**死锁根因修复**
- periodicThinkLoop:1015 orphaned lock → 删除（字段已原子化）
- RecordUserMessage 隔离为 recordMu
- atomic.Int64 替换 lastUserMessage/lastThinkTime 等

**MD3 / Android 17 主题**
- 毛玻璃卡片 (backdrop-filter)
- MD3 色彩令牌 (pink primary #f472b6)
- icons.js 独立矢量图标库 + 运行时 emoji 替换
- 无边框卡片、圆角按钮、阴影层次

**上下文持久化**
- AddMessage → saveToDB 异步写 PostgreSQL
- LoadFromDB 恢复 (admin-session-main + 懒加载)
- LLMMessage.Timestamp 字段

**群聊与适配器**
- group_ambient 模式: 非@消息让 LLM 自己判断是否插话
- 戳一戳动作消息总是回复
- NapCat 打字状态 (set_input_status, 最小3秒显示)
- HTTP API 配置 (http_url/http_token)

**知识库 & 防编造**
- knowledge.CanHandle 对 chat 意图也触发
- 关键词预筛选避免无关 embedding 调用
- persona + synthesizer 三重诚实规则
- 工具结果持久化到会话历史

**平台桥接器**
- detached:true Go进程独立存活
- ethend 重启自动接管已运行服务
- stop() 接管模式 taskkill/F/ PID
- Windows netstat 替代 fuser 获取 PID
- 重复适配器种子逻辑修复
- 失败转发日志 Direction: error

**崩溃诊断**
- crashlog 包 (Recover + WrapHTTP + LLMCall)
- /api/v1/debug/goroutines 端点
- thinker 操作日志 + 30s stats
- 日志写入 logs/ 目录持久化

Co-Authored-By: Claude <noreply@anthropic.com>

backend/ai-core/internal/subsession/knowledge_provider.go

@@ -3,6 +3,7 @@ package subsession
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"git.yeij.top/AskaEth/Cyrene/ai-core/internal/model"
@@ -24,16 +25,30 @@ func (p *KnowledgeProvider) Type() model.SubSessionType {
 	return model.SubSessionKnowledge
 }
 
-func (p *KnowledgeProvider) CanHandle(_ context.Context, intent *model.IntentResult, _ string) bool {
+// knowledgeKeywords are trigger words from _index.md. Only run expensive embedding search if message matches.
+var knowledgeKeywords = []string{
+	"翁法罗斯", "泰坦", "城邦", "黑潮", "帝皇权杖", "黄金裔",
+	"白厄", "阿格莱雅", "缇宝", "万敌", "那刻夏", "遐蝶", "风堇", "赛飞儿", "海瑟音", "刻律德菈",
+	"哀丽秘榭", "昔涟", "星神", "浮黎", "轮回", "始源命途", "无漏净子",
+	"剧情", "结局", "逐火", "盗火", "火种", "奥赫玛", "来古士",
+	"世界观", "设定", "哲学", "浪漫", "哀怜", "有瑕",
+}
+
+func (p *KnowledgeProvider) CanHandle(_ context.Context, intent *model.IntentResult, userMessage string) bool {
 	if intent == nil {
 		return true
 	}
-	// Activate for technical questions, how-to queries, and factual questions
 	switch intent.Primary {
 	case "knowledge", "technical", "how_to", "factual", "research":
 		return true
 	case "chat":
-		// For general chat, only search if there might be relevant info
+		// 仅当消息包含知识库相关关键词时才触发检索，避免每次聊天都跑 embedding
+		msg := strings.ToLower(userMessage)
+		for _, kw := range knowledgeKeywords {
+			if strings.Contains(msg, strings.ToLower(kw)) {
+				return true
+			}
+		}
 		return false
 	}
 	return true