feat: 增加打手工单备注

apps/backend/src/db/migrations/020_worker_order_notes.sql

@@ -0,0 +1,12 @@
+-- 020_worker_order_notes.sql —— 打手工单备注。
+--
+-- 整单与拼单份额分别保存，确保拼单打手只能查看和修改自己的备注。
+
+ALTER TABLE work_orders
+  ADD COLUMN IF NOT EXISTS worker_note TEXT NOT NULL DEFAULT '';
+
+ALTER TABLE work_order_shares
+  ADD COLUMN IF NOT EXISTS worker_note TEXT NOT NULL DEFAULT '';
+
+COMMENT ON COLUMN work_orders.worker_note IS '整单打手维护的个人备注';
+COMMENT ON COLUMN work_order_shares.worker_note IS '拼单打手维护的个人备注';

apps/backend/src/db/migrations/021_worker_order_notes_by_worker.sql

@@ -0,0 +1,14 @@
+-- 021_worker_order_notes_by_worker.sql —— 按打手保存工单备注。
+--
+-- 工单可重新分配，拼单也有多个打手；备注必须按工单和打手独立存储。
+
+CREATE TABLE IF NOT EXISTS worker_work_order_notes (
+  work_order_id BIGINT NOT NULL REFERENCES work_orders(id) ON DELETE CASCADE,
+  worker_id BIGINT NOT NULL REFERENCES worker_users(id) ON DELETE CASCADE,
+  note TEXT NOT NULL DEFAULT '',
+  created_at TIMESTAMPTZ NOT NULL,
+  updated_at TIMESTAMPTZ NOT NULL,
+  PRIMARY KEY (work_order_id, worker_id)
+);
+
+COMMENT ON TABLE worker_work_order_notes IS '打手维护的个人工单备注';