fix: use relative asset base for portable build output

Built index.html now references ./assets/... instead of /assets/...
so the dist folder works when opened directly (file://), served from a
subpath (github pages project site, netlify deploy preview, etc.), or
any non-root path. Previously the absolute-root paths produced a blank
page with module load failures in those environments.

Also ignore .claude/ local scratch dir.

vite.config.js

@@ -3,6 +3,9 @@ import { svelte } from '@sveltejs/vite-plugin-svelte';
 
 export default defineConfig({
     plugins: [svelte()],
+    // Relative asset paths — makes the built index.html work when opened
+    // directly (file://) or served from any subpath, not just the server root.
+    base: './',
     server: {
         port: 8080,
     },