refactor: 重构Todo合约验证模式，分离插入与更新校验逻辑

- 重构Todo合约验证模式，分离插入和更新数据的校验Schema，并移除不必要的字段。

src/orpc/contracts/todo.ts

@@ -7,11 +7,7 @@ import {
 import { z } from 'zod'
 import { todoTable } from '@/db/schema'
 
-const selectSchema = createSelectSchema(todoTable).omit({
+const selectSchema = createSelectSchema(todoTable)
-  id: true,
-  createdAt: true,
-  updatedAt: true,
-})
 
 const insertSchema = createInsertSchema(todoTable).omit({
   id: true,
@@ -19,7 +15,11 @@ const insertSchema = createInsertSchema(todoTable).omit({
   updatedAt: true,
 })
 
-const updateSchema = createUpdateSchema(todoTable)
+const updateSchema = createUpdateSchema(todoTable).omit({
+  id: true,
+  createdAt: true,
+  updatedAt: true,
+})
 
 export const todoContract = {
   list: oc.input(z.void()).output(z.array(selectSchema)),