押金解冻天数可配置与待解冻押金扣减，超时订单保留记录

apps/backend/src/db/migrations/010_worker_deposit_unfreeze.sql

@@ -0,0 +1,22 @@
+ALTER TABLE worker_wallets
+  ADD COLUMN pending_unfreeze_amount INTEGER NOT NULL DEFAULT 0;
+
+CREATE TABLE IF NOT EXISTS worker_deposit_unfreezes (
+  id BIGSERIAL PRIMARY KEY,
+  worker_id BIGINT NOT NULL REFERENCES worker_users(id) ON DELETE CASCADE,
+  work_order_id BIGINT NOT NULL REFERENCES work_orders(id) ON DELETE CASCADE,
+  amount INTEGER NOT NULL,
+  unfreeze_at TIMESTAMPTZ NOT NULL,
+  status TEXT NOT NULL DEFAULT 'pending',
+  released_at TIMESTAMPTZ,
+  created_at TIMESTAMPTZ NOT NULL,
+  updated_at TIMESTAMPTZ NOT NULL
+);
+
+CREATE INDEX idx_worker_deposit_unfreezes_scan
+  ON worker_deposit_unfreezes(status, unfreeze_at);
+CREATE INDEX idx_worker_deposit_unfreezes_worker
+  ON worker_deposit_unfreezes(worker_id, status);
+
+COMMENT ON COLUMN worker_wallets.pending_unfreeze_amount IS '待解冻押金：验收通过后 3 天到账';
+COMMENT ON TABLE worker_deposit_unfreezes IS '押金解冻计划：验收通过后进入待解冻，到期自动转入可用余额';

apps/backend/src/db/migrations/011_work_order_last_worker.sql

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+ALTER TABLE work_orders
+  ADD COLUMN last_assigned_worker_id BIGINT REFERENCES worker_users(id) ON DELETE SET NULL;
+
+CREATE INDEX idx_work_orders_last_worker
+  ON work_orders(last_assigned_worker_id, status, id DESC);
+
+COMMENT ON COLUMN work_orders.last_assigned_worker_id IS '最近一次接单的打手，超时/取消后保留，用于打手查看历史记录';