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/components/header/Header.tsx

@@ -4,6 +4,7 @@ import { chatStore } from '~/lib/stores/chat';
 import { classNames } from '~/utils/classNames';
 import { HeaderActionButtons } from './HeaderActionButtons.client';
 import { ChatDescription } from '~/lib/persistence/ChatDescription.client';
+import { SlateWordmark } from './SlateWordmark';
 
 export function Header() {
   const chat = useStore(chatStore);
@@ -17,10 +18,8 @@ export function Header() {
     >
       <div className="flex items-center gap-2 z-logo text-bolt-elements-textPrimary cursor-pointer">
         <div className="i-ph:sidebar-simple-duotone text-xl" />
-        <a href="/" className="text-2xl font-semibold text-accent flex items-center">
-          {/* <span className="i-bolt:logo-text?mask w-[46px] inline-block" /> */}
-          <img src="/logo-light-styled.png" alt="logo" className="w-[90px] inline-block dark:hidden" />
-          <img src="/logo-dark-styled.png" alt="logo" className="w-[90px] inline-block hidden dark:block" />
+        <a href="/" className="text-2xl font-semibold flex items-center text-bolt-elements-textPrimary">
+          <SlateWordmark className="h-8 w-auto" />
         </a>
       </div>
       {chat.started && ( // Display ChatDescription and HeaderActionButtons only when the chat has started.