feat(web): scaffold SvelteKit SPA with Tailwind + adapter-static

- SvelteKit 2.x + Svelte 5 + TypeScript + Vite 5
- adapter-static with fallback:'index.html' for SPA deep-link routing
- Tailwind configured with dark-only palette matching spec
- Placeholder landing page at /
- Committed web/build/index.html placeholder (via .gitignore negation) so
  go:embed works before the SvelteKit build has been run

web/svelte.config.js

@@ -0,0 +1,18 @@
+import adapter from '@sveltejs/adapter-static';
+import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
+
+export default {
+  preprocess: vitePreprocess(),
+  kit: {
+    adapter: adapter({
+      pages: 'build',
+      assets: 'build',
+      fallback: 'index.html',
+      precompress: false,
+      strict: false
+    }),
+    files: {
+      assets: 'static'
+    }
+  }
+};