fix: remove medium theme, fix navbar re-render, fix Node.js env loading

- Remove 'medium' theme from dashboard and marketplace; keep only light/dark
- Marketplace: move public pages into (public)/ route group so header/footer
  persist across navigations without re-rendering (eliminates usePathname)
- MarketplaceShell is now a pure context provider; chrome lives in
  (public)/layout.tsx which Next.js holds stable across navigations
- WorkspaceFrame: remove history.replaceState and standalone-route logic
- Docker API: bypass npm run dev to avoid node --env-file in containers
- Add scripts/run-with-env-file.cjs for Node.js < 20.6 compatibility;
  update apps/api/package.json dev script to use it

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

apps/dashboard/src/app/layout.tsx

@@ -26,7 +26,7 @@ export default function RootLayout({ children }: { children: React.ReactNode })
         <script
           dangerouslySetInnerHTML={{
             __html:
-              "(function(){try{var m=document.cookie.match(/(?:^|; )rentaldrivego-theme=([^;]+)/);var theme=m?decodeURIComponent(m[1]):(localStorage.getItem('rentaldrivego-theme')||localStorage.getItem('dashboard-theme'));if(theme!=='light'&&theme!=='medium'&&theme!=='dark'){theme=window.matchMedia('(prefers-color-scheme: dark)').matches?'dark':'light'}var rootTheme=theme==='light'?'light':'dark';document.documentElement.classList.remove('light','dark');document.documentElement.classList.add(rootTheme);document.documentElement.style.colorScheme=rootTheme;document.body&&document.body.setAttribute('data-theme',theme)}catch(e){}})();",
+              "(function(){try{var m=document.cookie.match(/(?:^|; )rentaldrivego-theme=([^;]+)/);var theme=m?decodeURIComponent(m[1]):(localStorage.getItem('rentaldrivego-theme')||localStorage.getItem('dashboard-theme'));if(theme!=='light'&&theme!=='dark'){theme=window.matchMedia('(prefers-color-scheme: dark)').matches?'dark':'light'}var rootTheme=theme==='light'?'light':'dark';document.documentElement.classList.remove('light','dark');document.documentElement.classList.add(rootTheme);document.documentElement.style.colorScheme=rootTheme;document.body&&document.body.setAttribute('data-theme',theme)}catch(e){}})();",
           }}
         />
       </head>

apps/dashboard/src/app/sign-in/[[...sign-in]]/SignInPageClient.tsx

@@ -92,7 +92,7 @@ export default function SignInPageClient({ embedded = false }: { embedded?: bool
     }
 
     if (
-      (requestedTheme === 'light' || requestedTheme === 'medium' || requestedTheme === 'dark') &&
+      (requestedTheme === 'light' || requestedTheme === 'dark') &&
       requestedTheme !== theme
     ) {
       setTheme(requestedTheme)