chore: deploy to Cloudflare Pages and update branding

- Add Cloudflare Pages deployment for landing page (snapotter.com) and
  docs (docs.snapotter.com)
- Create deploy-landing.yml and update deploy-docs.yml workflows
- Update CI to ignore apps/landing/** paths
- Fix logo transparency (remove white background) across all apps
- Recreate social-preview.png with SnapOtter branding
- Update all docs URLs from GitHub Pages to docs.snapotter.com
- Update VitePress config: light theme default, fix llms.txt paths
- Add .vitepress/cache/ and .env.* to gitignore

apps/web/src/pages/login-page.tsx

@@ -25,7 +25,7 @@ export function LoginPage() {
       const data = await res.json();
       setToken(data.token);
       // Store username for settings display
-      localStorage.setItem("ashim-username", data.user?.username || username);
+      localStorage.setItem("snapotter-username", data.user?.username || username);
       // Redirect to password change if required, otherwise go home
       if (data.user?.mustChangePassword) {
         window.location.href = "/change-password";