feat(health): 护理计划实体与服务 — Phase 1 关怀引擎 MVP 第一步

新增护理计划（Care Plan）完整 CRUD：3 张表（care_plans / care_plan_items /
care_plan_outcomes）、3 个 SeaORM Entity、15 个 API 端点、4 个事件常量、
2 个权限码。支持透析/慢性/预防/康复计划类型，条目分干预/监测/目标/教育四类，
预后测量含基线/目标/当前值追踪。

crates/erp-health/src/event.rs

@@ -57,6 +57,12 @@ pub const POINTS_EXPIRED: &str = "points.expired";
 pub const POINTS_EARNED: &str = "points.earned";
 pub const POINTS_EXCHANGED: &str = "points.exchanged";
 
+// 护理计划
+pub const CARE_PLAN_CREATED: &str = "care_plan.created";
+pub const CARE_PLAN_UPDATED: &str = "care_plan.updated";
+pub const CARE_PLAN_ACTIVATED: &str = "care_plan.activated";
+pub const CARE_PLAN_COMPLETED: &str = "care_plan.completed";
+
 /// 兼容旧签名 — 不做任何实际订阅（逻辑已迁移到 on_startup）
 pub fn register_handlers(_bus: &EventBus) {
     // 事件处理器已迁移到 on_startup → register_handlers_with_state