Enable KeyStatic CMS for production

Changes:
- Added Netlify adapter for server-side rendering
- Changed output mode from static to server
- Updated KeyStatic storage from local to GitHub
- Removed SKIP_KEYSTATIC from Netlify build
- KeyStatic Admin UI will be available at /keystatic

Features:
- Server-side rendering with Netlify Functions
- GitHub integration for content management
- Production-ready KeyStatic Admin UI

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

.netlify/v1/functions/ssr/ssr.mjs

@@ -0,0 +1,12 @@
+
+				import createSSRHandler from './.netlify/build/entry.mjs';
+				export default createSSRHandler({"cacheOnDemandPages":false});
+				export const config = {
+					includedFiles: ['**/*'],
+					name: 'Astro SSR',
+					nodeBundler: 'none',
+					generator: '@astrojs/netlify@6.6.4',
+					path: '/*',
+					preferStatic: true,
+				};
+