desktop: make readme more accurate

packages/desktop/README.md

@@ -2,6 +2,10 @@
 
 Native OpenCode desktop app, built with Tauri v2.
 
+## Prerequisites
+
+Building the desktop app requires additional Tauri dependencies (Rust toolchain, platform-specific libraries). See the [Tauri prerequisites](https://v2.tauri.app/start/prerequisites/) for setup instructions.
+
 ## Development
 
 From the repo root:
@@ -11,22 +15,18 @@ bun install
 bun run --cwd packages/desktop tauri dev
 ```
 
-This starts the Vite dev server on http://localhost:1420 and opens the native window.
-
-If you only want the web dev server (no native shell):
+## Build
 
 ```bash
-bun run --cwd packages/desktop dev
+bun run --cwd packages/desktop tauri build
 ```
 
-## Build
+## Troubleshooting
+
+### Rust compiler not found
 
-To create a production `dist/` and build the native app bundle:
+If you see errors about Rust not being found, install it via [rustup](https://rustup.rs/):
 
 ```bash
-bun run --cwd packages/desktop tauri build
+curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
 ```
-
-## Prerequisites
-
-Running the desktop app requires additional Tauri dependencies (Rust toolchain, platform-specific libraries). See the [Tauri prerequisites](https://v2.tauri.app/start/prerequisites/) for setup instructions.