新增: Phase2 阶段收尾（Sprint 1-20）

重构：删 5 零引用 crate（df-evolve/plugin/stages/task/traceability）+ 清死模块、ai.rs 拆 11 子 module、ai.ts 拆 6 composable、i18n 拆目录
功能：知识库全栈（df-project/scan + CRUD + 时间线 + 前端）、Settings 拆分、appSettings KV 迁移、模型池、LLM 并发 Semaphore
修复：审批持久化根治、ConditionEngine 默认拒绝、NodeRegistry unimplemented 清除、promote 补偿删除、工具结果截断 50KB、路径校验防 symlink 逃逸
文档：B-03 人工审批设计、决策记录三分档、规格契约自检、经验记录、todo 看板、PROGRESS 更新

详见 PROGRESS.md。src-tauri/儿童每日打卡应用/ 与本项目无关，已排除。

src-tauri/src/commands/knowledge_timeline.rs

@@ -0,0 +1,123 @@
+//! 知识生命线记录器 — 统一入口,各业务流程只调一行
+//!
+//! 设计目标:
+//! - 事件记录逻辑不散落在各业务流程内部(提取/注入/状态变更),集中于此模块
+//! - fire-and-forget 友好:便捷方法内部吞掉错误(只 warn),调用方无需处理 Result
+//! - 易扩展:新事件类型只加一个便捷方法 + 一行 context 构造,不改主流程
+
+use std::sync::Arc;
+
+use df_core::types::new_id;
+use df_storage::crud::KnowledgeEventsRepo;
+use df_storage::db::Database;
+use df_storage::models::KnowledgeEventRecord;
+
+use super::now_millis;
+
+/// 事件类型常量(生命线节点;归档复用 status_changed 的 to=archived,不单列)
+pub const EVENT_CREATED: &str = "created";
+pub const EVENT_EXTRACTED: &str = "extracted";
+pub const EVENT_STATUS_CHANGED: &str = "status_changed";
+pub const EVENT_REFERENCED: &str = "referenced";
+
+/// 知识生命线记录器 — 持有 DB 句柄,提供便捷事件写入方法
+///
+/// 用法:`KnowledgeTimeline::new(&state.db).record_xxx(...).await`
+///
+/// 异步策略(按路径热度,非 bug,刻意不一致):
+/// - 热路径(对话注入 build_knowledge_context / 提炼 extract):整块已在 spawn 任务内,
+///   此处直接 await = 对用户 fire-and-forget,不阻塞 AI 对话
+/// - 低频命令(状态变更 / 创建):事件写入 ms 级,直接 await 比 detached spawn 更简单
+/// 便捷方法内部 `fire()` 已吞错误(warn 不阻断),调用方无需处理 Result。
+pub struct KnowledgeTimeline {
+    db: Arc<Database>,
+}
+
+impl KnowledgeTimeline {
+    pub fn new(db: &Arc<Database>) -> Self {
+        Self { db: db.clone() }
+    }
+
+    /// 通用写入(底层入口,便捷方法均经此)
+    pub async fn record(
+        &self,
+        knowledge_id: &str,
+        event_type: &str,
+        source_ref: Option<String>,
+        context_json: Option<String>,
+    ) -> Result<(), String> {
+        let record = KnowledgeEventRecord {
+            id: new_id(),
+            knowledge_id: knowledge_id.to_string(),
+            event_type: event_type.to_string(),
+            source_ref,
+            context_json,
+            timestamp: now_millis(),
+        };
+        KnowledgeEventsRepo::new(&self.db)
+            .insert(record)
+            .await
+            .map_err(|e| e.to_string())?;
+        Ok(())
+    }
+
+    /// 手动录入产生(context: method)
+    pub async fn record_created(&self, knowledge_id: &str, method: &str) {
+        let ctx = serde_json::json!({ "method": method }).to_string();
+        self.fire(knowledge_id, EVENT_CREATED, Some("manual".into()), Some(ctx)).await;
+    }
+
+    /// AI 对话提炼产生(context: conv_id / conv_title / reasoning)
+    pub async fn record_extracted(
+        &self,
+        knowledge_id: &str,
+        conv_id: &str,
+        conv_title: &str,
+        reasoning: &str,
+    ) {
+        let ctx = serde_json::json!({
+            "conv_id": conv_id,
+            "conv_title": conv_title,
+            "reasoning": reasoning,
+        })
+        .to_string();
+        self.fire(
+            knowledge_id,
+            EVENT_EXTRACTED,
+            Some(format!("conv:{}", conv_id)),
+            Some(ctx),
+        )
+        .await;
+    }
+
+    /// 被检索命中/注入(context: conv_id / query)
+    pub async fn record_referenced(&self, knowledge_id: &str, conv_id: &str, query: &str) {
+        let ctx = serde_json::json!({ "conv_id": conv_id, "query": query }).to_string();
+        self.fire(
+            knowledge_id,
+            EVENT_REFERENCED,
+            Some(format!("conv:{}", conv_id)),
+            Some(ctx),
+        )
+        .await;
+    }
+
+    /// 状态变更(context: from / to;to=published=审核通过,to=archived=归档)
+    pub async fn record_status_change(&self, knowledge_id: &str, from: &str, to: &str) {
+        let ctx = serde_json::json!({ "from": from, "to": to }).to_string();
+        self.fire(knowledge_id, EVENT_STATUS_CHANGED, None, Some(ctx)).await;
+    }
+
+    /// 内部:写入并吞错误(fire-and-forget,失败只 warn 不阻断主流程)
+    async fn fire(
+        &self,
+        knowledge_id: &str,
+        event_type: &str,
+        source_ref: Option<String>,
+        context_json: Option<String>,
+    ) {
+        if let Err(e) = self.record(knowledge_id, event_type, source_ref, context_json).await {
+            tracing::warn!("知识生命线事件写入失败(非阻断) [{}]: {}", event_type, e);
+        }
+    }
+}