docs: mise installation command (#2938)

packages/web/src/components/Lander.astro

@@ -131,6 +131,18 @@ if (image) {
           </span>
         </button>
       </div>
+      <div class="col4">
+        <h3>Mise</h3>
+        <button class="command" data-command="mise use --pin -g ubi:sst/opencode">
+          <code>
+            <span>mise use --pin -g</span> <span class="highlight">ubi:sst/opencode</span>
+          </code>
+          <span class="copy">
+            <CopyIcon />
+            <CheckIcon />
+          </span>
+        </button>
+      </div>
     </section>
 
     <section class="images">

packages/web/src/content/docs/index.mdx

@@ -106,6 +106,12 @@ You can also install it with the following commands:
   npm install -g opencode-ai
   ```
 
+- **Using Mise**
+
+  ```bash
+  mise use --pin -g ubi:sst/opencode
+  ```
+
 Support for installing OpenCode on Windows using Bun is currently in progress.
 
 You can also grab the binary from the [Releases](https://github.com/sst/opencode/releases).