docs: 同步 AGENTS.md 至 Drizzle v1 beta 并添加开发原则

- 所有 AGENTS.md 新增「开发原则」：不向后兼容、改代码必须同步文档、前向迁移
- 根 AGENTS.md: 更新 Database 段落为 Drizzle v1 beta + postgres-js + RQBv2
- server AGENTS.md: 更新 tech stack、目录结构、ORPC 示例、数据库段落
  - drizzle-zod → drizzle-orm/zod
  - bun-sql → postgres-js
  - RQBv1 回调 → RQBv2 对象语法
  - 新增 relations.ts 和 DB instance 示例
- desktop AGENTS.md: 添加开发原则和文档同步规则

apps/server/AGENTS.md

@@ -11,7 +11,7 @@ TanStack Start fullstack web app with ORPC (contract-first RPC).
 - **Package Manager**: Bun — **NOT npm / yarn / pnpm**
 - **Language**: TypeScript (strict mode)
 - **Styling**: Tailwind CSS v4
-- **Database**: PostgreSQL + Drizzle ORM
+- **Database**: PostgreSQL + Drizzle ORM v1 beta (`drizzle-orm/postgres-js`, RQBv2)
 - **State**: TanStack Query v5
 - **RPC**: ORPC (contract-first, type-safe)
 - **Build**: Vite + Nitro
@@ -72,7 +72,8 @@ src/
 │   │   └── types.ts       # Type exports
 │   └── db/
 │       ├── schema/        # Drizzle table definitions
-│       └── index.ts       # Database instance
+│       ├── relations.ts   # Drizzle relations (defineRelations, RQBv2)
+│       └── index.ts       # Database instance (postgres-js driver)
 ├── env.ts                 # Environment variable validation
 ├── router.tsx             # Router configuration
 ├── routeTree.gen.ts       # Auto-generated (DO NOT EDIT)
@@ -84,7 +85,7 @@ src/
 ### 1. Define Contract (`src/server/api/contracts/feature.contract.ts`)
 ```typescript
 import { oc } from '@orpc/contract'
-import { createSelectSchema } from 'drizzle-zod'
+import { createSelectSchema } from 'drizzle-orm/zod'
 import { z } from 'zod'
 import { featureTable } from '@/server/db/schema'
 
@@ -101,7 +102,9 @@ import { db } from '../middlewares'
 import { os } from '../server'
 
 export const list = os.feature.list.use(db).handler(async ({ context }) => {
-  return await context.db.query.featureTable.findMany()
+  return await context.db.query.featureTable.findMany({
+    orderBy: { createdAt: 'desc' },
+  })
 })
 ```
 
@@ -125,8 +128,14 @@ const { data } = useSuspenseQuery(orpc.feature.list.queryOptions())
 const mutation = useMutation(orpc.feature.create.mutationOptions())
 ```
 
-## Database Schema (Drizzle)
+## Database (Drizzle ORM v1 beta)
 
+- **Driver**: `drizzle-orm/postgres-js` (NOT `bun-sql`)
+- **Validation**: `drizzle-orm/zod` (built-in, NOT separate `drizzle-zod` package)
+- **Relations**: Defined via `defineRelations()` in `src/server/db/relations.ts`
+- **Query**: RQBv2 — use `db.query.tableName.findMany()` with object-style `orderBy` and `where`
+
+### Schema Definition
 ```typescript
 import { pgTable, text, timestamp, uuid } from 'drizzle-orm/pg-core'
 import { sql } from 'drizzle-orm'
@@ -139,6 +148,44 @@ export const myTable = pgTable('my_table', {
 })
 ```
 
+### Relations (RQBv2)
+```typescript
+// src/server/db/relations.ts
+import { defineRelations } from 'drizzle-orm'
+import * as schema from './schema'
+
+export const relations = defineRelations(schema, (r) => ({
+  // Define relations here using r.one / r.many / r.through
+}))
+```
+
+### DB Instance
+```typescript
+// src/server/db/index.ts
+import { drizzle } from 'drizzle-orm/postgres-js'
+import { relations } from '@/server/db/relations'
+import * as schema from '@/server/db/schema'
+
+const db = drizzle({
+  connection: env.DATABASE_URL,
+  schema,
+  relations,
+})
+```
+
+### RQBv2 Query Examples
+```typescript
+// Object-style orderBy (NOT callback style)
+const todos = await db.query.todoTable.findMany({
+  orderBy: { createdAt: 'desc' },
+})
+
+// Object-style where
+const todo = await db.query.todoTable.findFirst({
+  where: { id: someId },
+})
+```
+
 ## Code Style
 
 ### Formatting (Biome)
@@ -197,6 +244,14 @@ export const env = createEnv({
 })
 ```
 
+## Development Principles
+
+> **These principles apply to ALL code changes. Agents MUST follow them on every task.**
+
+1. **No backward compatibility** — This project is in rapid iteration. Always use the latest API and patterns. Never keep deprecated code paths or old API fallbacks.
+2. **Always sync documentation** — When code changes, immediately update all related documentation (`AGENTS.md`, `README.md`, inline code examples). Code and docs must never drift apart.
+3. **Forward-only migration** — When upgrading dependencies, fully adopt the new API. Don't mix old and new patterns.
+
 ## Critical Rules
 
 **DO:**
@@ -204,6 +259,9 @@ export const env = createEnv({
 - Use `@/*` path aliases
 - Include `createdAt`/`updatedAt` on all tables
 - Use `ORPCError` with proper codes
+- Use `drizzle-orm/zod` (NOT `drizzle-zod`) for schema validation
+- Use RQBv2 object syntax for `orderBy` and `where`
+- Update `AGENTS.md` and other docs whenever code patterns change
 
 **DON'T:**
 - Use `npm`, `npx`, `node`, `yarn`, `pnpm` — always use `bun` / `bunx`
@@ -211,3 +269,7 @@ export const env = createEnv({
 - Use `as any`, `@ts-ignore`, `@ts-expect-error`
 - Commit `.env` files
 - Use empty catch blocks
+- Import from `drizzle-zod` (use `drizzle-orm/zod` instead)
+- Use RQBv1 callback-style `orderBy` / old `relations()` API
+- Use `drizzle-orm/bun-sql` driver (use `drizzle-orm/postgres-js`)
+- Leave docs out of sync with code changes