docs: add AGENTS.md with Cloud Agent development instructions

Co-authored-by: 晴天 <1186258278@users.noreply.github.com>

AGENTS.md

@@ -0,0 +1,39 @@
+# AGENTS.md
+
+## Cursor Cloud specific instructions
+
+### Overview
+
+ClawPanel is a cross-platform AI Agent management panel (Vanilla JS + Vite frontend, optional Rust/Tauri desktop backend). In Cloud Agent environments, only the **Web development mode** is relevant—no Rust/Tauri compilation is needed.
+
+### Running the development server
+
+```bash
+npm run dev
+```
+
+This starts Vite on port 1420 with a `dev-api.js` plugin that provides mock/real backend API endpoints. Open http://localhost:1420 in Chrome. The default password is pre-filled on the login screen (the panel stores passwords in `~/.openclaw/clawpanel.json`).
+
+### Running tests
+
+```bash
+node --test tests/*.test.js
+```
+
+Note: Test 30 (`buildSnapshot.isLatest works against KERNEL_TARGET`) has a pre-existing failure unrelated to environment setup.
+
+### Building
+
+```bash
+npm run build
+```
+
+Build output goes to `dist/`.
+
+### Key gotchas
+
+- The app uses `package-lock.json`; always use **npm** (not pnpm/yarn).
+- No ESLint or Prettier configured for JS; the CI only checks Rust formatting (`cargo fmt --check`) and Rust lint (`cargo clippy`).
+- OpenClaw Gateway (port 18789) is an optional external dependency. The panel UI loads fine without it but AI chat features will not function.
+- Rust/Tauri system deps (libwebkit2gtk, etc.) are only needed for `npm run tauri dev`/`npm run tauri build`. They are NOT needed for web-only development.
+- The Vite config reads `~/.openclaw/openclaw.json` at startup for the Gateway WebSocket proxy port. If the file doesn't exist, it defaults to port 18789.