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

.gitignore

@@ -1,4 +1,5 @@
 node_modules
+.yarn
 
 # Output
 .output
@@ -27,4 +28,3 @@ package-lock.json
 
 # Git worktrees
 .worktrees
-