feat: rebrand to Slate (logo, palette, copy, Launch button)

- Wordmark SVG + favicon (#FF1F8F → #00D4FF gradient)
- Page title: Slate — AI App Builder
- Header logo via inline component (no external font deps)
- Deploy button label -> Launch
- Chat placeholder + example prompt rebranded
- Replace upstream accent palette with magenta primary, add cyan2 for accents
- Settings tab notes upstream remains stackblitz-labs/bolt.diy

app/routes/git.tsx

@@ -7,7 +7,7 @@ import { Header } from '~/components/header/Header';
 import BackgroundRays from '~/components/ui/BackgroundRays';
 
 export const meta: MetaFunction = () => {
-  return [{ title: 'Bolt' }, { name: 'description', content: 'Talk with Bolt, an AI assistant from StackBlitz' }];
+  return [{ title: 'Bolt' }, { name: 'description', content: 'Talk with Slate, an AI assistant from StackBlitz' }];
 };
 
 export async function loader(args: LoaderFunctionArgs) {