fix: handle undefined githubStars in tool detail page

Use loose equality (!=) instead of strict equality (!==) to check for
both null and undefined values. This prevents runtime TypeError when
githubStars is undefined.

Fixes: Cannot read properties of undefined (reading 'toLocaleString')

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

apps/web/src/app/tool/[...slug]/page.tsx

@@ -419,7 +419,7 @@ export default function ToolDetailPage({
                     {tool.npmDownloadsLastMonth?.toLocaleString() || '0'}
                   </p>
                 </div>
-                {tool.githubStars !== null && (
+                {tool.githubStars != null && (
                   <div>
                     <p className="text-sm text-foreground-secondary mb-1">GitHub Stars</p>
                     <p className="text-2xl font-bold text-foreground">