docs: 更新 AGENTS.md 文档结构和内容

- 新增根目录 AGENTS.md 作为 monorepo 总览
- 移动 desktop AGENTS.md 从 src-tauri/ 到 apps/desktop/
- 修正 server AGENTS.md 目录结构 (src/server/api/ 而非 src/orpc/)
- 明确 desktop 为纯 Tauri 壳子，无前端代码，通过 sidecar 加载 server

apps/desktop/AGENTS.md

@@ -0,0 +1,171 @@
+# AGENTS.md - Desktop App Guidelines
+
+Tauri v2 desktop shell - a lightweight wrapper that loads the server app via sidecar.
+
+## Architecture
+
+- **Type**: Tauri v2 desktop application (shell only)
+- **Design**: Tauri provides native desktop APIs; all web logic handled by sidecar
+- **Sidecar**: The compiled server binary runs as a child process
+- **Dev mode**: Connects to `localhost:3000` (requires server dev running)
+- **Prod mode**: Automatically starts sidecar binary
+
+**This app has NO frontend src** - it loads the server app entirely.
+
+## Commands
+
+```bash
+# Development (from apps/desktop/)
+bun dev                    # Copy sidecar + start Tauri dev
+
+# Build
+bun build                  # Copy sidecar + build Tauri installer
+
+# Rust Commands (from src-tauri/)
+cargo check                # Compile check
+cargo clippy               # Linter
+cargo fmt                  # Formatter
+cargo test                 # Run tests
+cargo test test_name -- --nocapture  # Single test with output
+```
+
+## Directory Structure
+
+```
+apps/desktop/
+├── src-tauri/             # Rust Tauri code
+│   ├── src/
+│   │   ├── main.rs        # Entry point (calls lib::run)
+│   │   ├── lib.rs         # Core app logic (plugins, commands, state)
+│   │   ├── commands/
+│   │   │   └── mod.rs     # Native desktop commands
+│   │   └── sidecar.rs     # Sidecar process management
+│   ├── binaries/          # Sidecar binaries (copied from server build)
+│   ├── capabilities/      # Tauri v2 permission config
+│   ├── icons/             # App icons
+│   ├── Cargo.toml         # Rust dependencies
+│   └── tauri.conf.json    # Tauri configuration
+├── copy.ts                # Script to copy server binary to binaries/
+├── package.json
+└── tsconfig.json
+```
+
+## Development Workflow
+
+1. **Start server dev first**: `cd ../server && bun dev`
+2. **Start Tauri**: `bun dev` (from apps/desktop/)
+3. Tauri connects to localhost:3000 with HMR support
+
+## Rust Code Style
+
+### Formatting
+- **Indent**: 4 spaces
+- **Line width**: 100 chars
+- Run `cargo fmt` before commit
+
+### Naming
+| Type | Convention | Example |
+|------|------------|---------|
+| Functions/variables | snake_case | `find_available_port` |
+| Types/structs/enums | PascalCase | `SidecarProcess` |
+| Constants | SCREAMING_SNAKE | `DEFAULT_PORT` |
+
+### Imports
+```rust
+// Order: std → external crates → internal modules (separated by blank lines)
+use std::sync::Mutex;
+
+use tauri::Manager;
+use tauri_plugin_shell::ShellExt;
+
+use crate::sidecar::SidecarProcess;
+```
+
+### Error Handling
+```rust
+// Use expect() with Chinese error messages
+let sidecar = app_handle
+    .shell()
+    .sidecar("server")
+    .expect("无法找到 server sidecar");
+
+// Log with emoji for clear feedback
+println!("✓ Sidecar 启动成功！");
+eprintln!("✗ Sidecar 启动失败");
+```
+
+### Async Code
+```rust
+// Use Tauri's async runtime for spawning
+tauri::async_runtime::spawn(async move {
+    let port = find_available_port(3000).await;
+    // ...
+});
+```
+
+## Tauri Patterns
+
+### Command Definition
+```rust
+#[tauri::command]
+fn greet(name: &str) -> String {
+    format!("Hello, {}!", name)
+}
+
+// Register in Builder
+.invoke_handler(tauri::generate_handler![commands::greet])
+```
+
+### State Management
+```rust
+struct SidecarProcess(Mutex<Option<CommandChild>>);
+
+// Register state
+app.manage(SidecarProcess(Mutex::new(None)));
+
+// Access state
+if let Some(state) = app_handle.try_state::<SidecarProcess>() {
+    *state.0.lock().unwrap() = Some(child);
+}
+```
+
+### Sidecar Lifecycle
+```rust
+// Start sidecar with environment
+let sidecar = app_handle
+    .shell()
+    .sidecar("server")
+    .expect("无法找到 server sidecar")
+    .env("PORT", port.to_string());
+
+// Cleanup on exit
+match event {
+    tauri::RunEvent::ExitRequested { .. } | tauri::RunEvent::Exit => {
+        if let Some(child) = process.take() {
+            let _ = child.kill();
+        }
+    }
+    _ => {}
+}
+```
+
+## Critical Rules
+
+**DO:**
+- Run `cargo fmt` and `cargo clippy` before commit
+- Use `expect("中文消息")` instead of `unwrap()`
+- Always cleanup sidecar on app exit
+- Declare sidecar in `tauri.conf.json` → `bundle.externalBin`
+
+**DON'T:**
+- Edit `gen/schemas/` (auto-generated)
+- Use `unwrap()` in production code without context
+- Block the async runtime (use `spawn_blocking`)
+
+## Pre-commit Checklist
+
+- [ ] `cargo fmt` - formatting
+- [ ] `cargo clippy` - linting
+- [ ] `cargo check` - compiles
+- [ ] `cargo test` - tests pass
+- [ ] Tauri app starts and exits cleanly