refactor: extract ColorManipulation component and pass icon/summary to AppPage

- Rename ColorPage → ColorManipulation (no AppPage wrapper inside)
- Move AppPage + title/description/icon to color/page.tsx, consistent with other tools
- AppPage now accepts icon prop directly; removes internal usePathname lookup and 'use client'
- All tool pages pass tool.summary as description and tool.icon as icon

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/(app)/ascii/page.tsx

@@ -11,7 +11,8 @@ export default function ASCIIPage() {
   return (
     <AppPage
       title={tool.title}
-      description={tool.description}
+      description={tool.summary}
+      icon={tool.icon}
     >
       <ASCIIConverter />
     </AppPage>