fix: use npm in quick start example

Author: steipete

src/pages/index.astro

@@ -99,12 +99,12 @@ import Layout from '../layouts/Layout.astro';
         <pre><code><span class="code-comment"># Clone and build</span>
 <span class="code-prompt">$</span> git clone https://github.com/clawdbot/clawdbot.git
 <span class="code-prompt">$</span> cd clawdbot
-<span class="code-prompt">$</span> bun install
-<span class="code-prompt">$</span> bun run build
-<span class="code-prompt">$</span> bun run ui:install
+<span class="code-prompt">$</span> npm install
+<span class="code-prompt">$</span> npm run build
+<span class="code-prompt">$</span> npm run ui:install
 
 <span class="code-comment"># Run the onboarding wizard</span>
-<span class="code-prompt">$</span> bun run clawdbot onboard</code></pre>
+<span class="code-prompt">$</span> npm run clawdbot onboard</code></pre>
       </div>
       <p class="quickstart-note">
         Works on macOS, Windows & Linux. Node ≥22 or bun required.