新增: 初始化 DevFlow 项目仓库

Tauri 2 + Vue 3 + Vite 6 桌面应用，Rust workspace 含 13 个 crate
(df-ai / df-storage / df-workflow / df-core / df-execute 等)。
核心能力：AI 聊天 agentic 循环(工具调用+人工审批)、工作流引擎、
任务/想法/项目/阶段管理、可追溯性，及配套前端组件。

src-tauri/src/commands/task.rs

@@ -0,0 +1,91 @@
+//! 任务相关命令
+
+use serde::Deserialize;
+use tauri::State;
+
+use df_core::types::new_id;
+use df_storage::models::TaskRecord;
+
+use crate::state::AppState;
+
+use super::now_millis;
+
+/// 创建任务入参
+#[derive(Debug, Deserialize)]
+pub struct CreateTaskInput {
+    pub project_id: String,
+    pub title: String,
+    #[serde(default)]
+    pub description: String,
+    #[serde(default = "default_priority")]
+    pub priority: i32,
+    pub branch_name: Option<String>,
+    pub assignee: Option<String>,
+}
+
+fn default_priority() -> i32 {
+    1
+}
+
+/// 列出任务，可按 project_id 过滤
+#[tauri::command]
+pub async fn list_tasks(
+    state: State<'_, AppState>,
+    project_id: Option<String>,
+) -> Result<Vec<TaskRecord>, String> {
+    let result = match project_id {
+        Some(pid) => state.tasks.query("project_id", &pid).await,
+        None => state.tasks.list_all().await,
+    };
+    result.map_err(|e| e.to_string())
+}
+
+/// 创建任务，返回完整记录
+#[tauri::command]
+pub async fn create_task(
+    state: State<'_, AppState>,
+    input: CreateTaskInput,
+) -> Result<TaskRecord, String> {
+    let now = now_millis();
+    let record = TaskRecord {
+        id: new_id(),
+        project_id: input.project_id,
+        title: input.title,
+        description: input.description,
+        status: "todo".to_string(),
+        priority: input.priority,
+        branch_name: input.branch_name,
+        assignee: input.assignee,
+        workflow_def_id: None,
+        base_branch: None,
+        created_at: now.clone(),
+        updated_at: now,
+    };
+    state
+        .tasks
+        .insert(record.clone())
+        .await
+        .map_err(|e| e.to_string())?;
+    Ok(record)
+}
+
+/// 更新任务单个字段（字段名走 df-storage 白名单校验）
+#[tauri::command]
+pub async fn update_task(
+    state: State<'_, AppState>,
+    id: String,
+    field: String,
+    value: String,
+) -> Result<bool, String> {
+    state
+        .tasks
+        .update_field(&id, &field, &value)
+        .await
+        .map_err(|e| e.to_string())
+}
+
+/// 删除任务
+#[tauri::command]
+pub async fn delete_task(state: State<'_, AppState>, id: String) -> Result<bool, String> {
+    state.tasks.delete(&id).await.map_err(|e| e.to_string())
+}