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/settings.rs

@@ -0,0 +1,47 @@
+//! 通用应用设置 KV IPC — 前端 localStorage 迁移目标
+//!
+//! 4 个 command 读写 `app_settings` 表(key/value JSON 字符串),承载主题、面板折叠态、
+//! 最近使用项等前端持久化偏好。返回统一 `Result<T, String>`。
+
+use std::collections::HashMap;
+
+use tauri::State;
+
+use crate::state::AppState;
+
+/// 取单个 key 的值(JSON 字符串),不存在返回 None
+#[tauri::command]
+pub async fn settings_get(
+    state: State<'_, AppState>,
+    key: String,
+) -> Result<Option<String>, String> {
+    state.settings.get(&key).await.map_err(|e| e.to_string())
+}
+
+/// 写 key/value(`INSERT OR REPLACE`),刷新 updated_at
+#[tauri::command]
+pub async fn settings_set(
+    state: State<'_, AppState>,
+    key: String,
+    value: String,
+) -> Result<bool, String> {
+    state.settings.set(&key, &value).await.map_err(|e| e.to_string())
+}
+
+/// 取全部 key/value(前端启动时一次性拉回恢复偏好)
+#[tauri::command]
+pub async fn settings_get_all(
+    state: State<'_, AppState>,
+) -> Result<HashMap<String, String>, String> {
+    let rows = state.settings.get_all().await.map_err(|e| e.to_string())?;
+    Ok(rows.into_iter().collect())
+}
+
+/// 删除单个 key
+#[tauri::command]
+pub async fn settings_delete(
+    state: State<'_, AppState>,
+    key: String,
+) -> Result<bool, String> {
+    state.settings.delete(&key).await.map_err(|e| e.to_string())
+}