feat: 通知系统(notifications表+CRUD接口+管理员接口)

migrations/011_add_notifications.sql

@@ -0,0 +1,34 @@
+-- ============================================
+-- 迁移: 011_add_notifications.sql
+-- 目的: 创建统一通知表，覆盖系统公告/个人通知/事件通知
+-- 日期: 2026-05-26
+-- ============================================
+
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS notifications (
+    id         SERIAL PRIMARY KEY,
+    scope      VARCHAR(16) NOT NULL DEFAULT 'user',
+    user_id    INTEGER REFERENCES users(id) ON DELETE CASCADE,
+    type       VARCHAR(32) NOT NULL,
+    title      VARCHAR(255) NOT NULL,
+    content    TEXT,
+    priority   VARCHAR(16) NOT NULL DEFAULT 'normal',
+    link       VARCHAR(512),
+    is_read    BOOLEAN NOT NULL DEFAULT false,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    expires_at TIMESTAMPTZ
+);
+
+CREATE INDEX IF NOT EXISTS idx_notifications_user
+    ON notifications(scope, user_id, created_at DESC);
+CREATE INDEX IF NOT EXISTS idx_notifications_all
+    ON notifications(scope, created_at DESC) WHERE scope = 'all';
+CREATE INDEX IF NOT EXISTS idx_notifications_expires
+    ON notifications(expires_at) WHERE expires_at IS NOT NULL;
+
+COMMENT ON TABLE notifications IS '统一通知表：scope=all 系统广播，scope=user 定向通知';
+COMMENT ON COLUMN notifications.scope IS '作用域: all(广播) / user(定向)';
+COMMENT ON COLUMN notifications.type IS '通知类型: system_maintenance / member_expiry / payment_success / version_update';
+
+COMMIT;