feat: Phase1 核心——模型/状态机 + SQLite Store(守卫+审批闸) + REST/WS API + daemon

- src/model: 复杂度分级、16 状态状态机、实体类型
- src/store: better-sqlite3 接 schema，transition 受 canTransition 守卫，
  decide 审批闸(reject 必带改进意见)，事件订阅广播，nextExecutable
- src/api: Fastify REST + ws 事件广播(/ws)
- src/daemon: maestrod 入口(env 配置，默认 ~/.maestro :4517)
- test: 9 个生命周期单测全过；typecheck/build 干净；REST+WS 端到端实跑验证

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/model/complexity.ts

@@ -0,0 +1,23 @@
+/** 任务复杂度：Hard / Medium / Easy（对应旧 todo skill 的 tier 1/2/3） */
+export type Complexity = 'hard' | 'medium' | 'easy';
+
+export const COMPLEXITY_ORDER: Record<Complexity, number> = { hard: 1, medium: 2, easy: 3 };
+export const COMPLEXITY_LABEL: Record<Complexity, string> = { hard: 'Hard', medium: 'Medium', easy: 'Easy' };
+
+/** 旧 todo skill 的 tier(1/2/3) ↔ 复杂度，用于迁移导入 */
+export const TIER_TO_COMPLEXITY: Record<number, Complexity> = { 1: 'hard', 2: 'medium', 3: 'easy' };
+export const COMPLEXITY_TO_TIER: Record<Complexity, number> = { hard: 1, medium: 2, easy: 3 };
+
+/** 前置闸：执行前是否需要用户确认（Hard / Medium 需要，Easy 不需要） */
+export function requiresPreGate(c: Complexity): boolean {
+  return c === 'hard' || c === 'medium';
+}
+
+/** Hard 必须先进 plan 分析 + 任务拆解 */
+export function mustDecompose(c: Complexity): boolean {
+  return c === 'hard';
+}
+
+export function isComplexity(v: unknown): v is Complexity {
+  return v === 'hard' || v === 'medium' || v === 'easy';
+}