chore(storybook): switch to yarn and fix Storybook compatibility

- Switch from bun to yarn with node_modules linker
- Downgrade Svelte to 5.46.1 for Storybook compatibility
- Switch Storybook framework from @storybook/sveltekit to @storybook/svelte-vite
- Downgrade Storybook packages to 10.1.11
- Add FSD path aliases to vite.config.ts
- Add Svelte plugin to Storybook viteFinal to handle .svelte files

config/storybook/main.ts

@@ -1,17 +1,59 @@
-import type { StorybookConfig } from '@storybook/sveltekit';
+import type { StorybookConfig } from '@storybook/svelte-vite';
+import {
+  dirname,
+  resolve,
+} from 'path';
+import { fileURLToPath } from 'url';
+import {
+  loadConfigFromFile,
+  mergeConfig,
+} from 'vite';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
 
 const config: StorybookConfig = {
-  "stories": [
-    "../src/**/*.mdx",
-    "../src/**/*.stories.@(js|ts|svelte)"
+  stories: [
+    '../../src/**/*.mdx',
+    '../../src/**/*.stories.@(js|ts|svelte)',
   ],
-  "addons": [
-    "@storybook/addon-svelte-csf",
-    "@chromatic-com/storybook",
-    "@storybook/addon-vitest",
-    "@storybook/addon-a11y",
-    "@storybook/addon-docs"
+  addons: [
+    {
+      name: '@storybook/addon-svelte-csf',
+      options: {
+        // Use modern template syntax for better performance
+        legacyTemplate: false,
+      },
+    },
+    '@chromatic-com/storybook',
+    '@storybook/addon-vitest',
+    '@storybook/addon-a11y',
+    '@storybook/addon-docs',
   ],
-  "framework": "@storybook/sveltekit"
+  framework: '@storybook/svelte-vite',
+  async viteFinal(config) {
+    // This attempts to find your actual vite.config.ts
+    const { config: userConfig } = await loadConfigFromFile(
+      { command: 'serve', mode: 'development' },
+      resolve(__dirname, '../../vite.config.ts'),
+    ) || {};
+
+    const mergedConfig = mergeConfig(config, {
+      // Merge resolve/alias parts to maintain path aliases
+      resolve: userConfig?.resolve || {},
+    });
+
+    const { svelte } = await import('@sveltejs/vite-plugin-svelte');
+    mergedConfig.plugins = mergedConfig.plugins || [];
+
+    // Add Svelte plugin to process @storybook's .svelte files
+    // This prevents Vite from trying to parse them before compilation
+    mergedConfig.plugins.unshift(svelte({
+      include: [/node_modules\/@storybook\/.+\.svelte$/],
+    }));
+
+    return mergedConfig;
+  },
 };
-export default config;
+
+export default config;