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/desktop/AGENTS.md

@@ -73,6 +73,14 @@ The `electron-builder.yml` `extraResources` config reads binaries directly from
 To build for a specific platform explicitly, use `bun dist:linux` / `bun dist:mac` / `bun dist:win` in `apps/desktop`.
 For single-arch output, use `bun dist:linux:x64`, `bun dist:linux:arm64`, `bun dist:mac:x64`, or `bun dist:mac:arm64`.
 
+## 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:**
@@ -84,3 +92,4 @@ For single-arch output, use `bun dist:linux:x64`, `bun dist:linux:arm64`, `bun d
 - Use `npm`, `npx`, `yarn`, or `pnpm`. Use `bun` for package management.
 - Include UI components or business logic in the desktop app.
 - Use `as any` or `@ts-ignore`.
+- Leave docs out of sync with code changes.