Add storybook and setup

Also updated yarn to version 3 to avoid an issue where both storybook and cypress depend on the same node module (string-width) but different versions. See: https://github.com/cypress-io/cypress/issues/27370\#issuecomment-1649715561

.storybook/main.cjs

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+module.exports = {
+  "stories": [
+    "../stories/**/*.stories.mdx",
+    "../stories/**/*.stories.@(js|jsx|ts|tsx|svelte)"
+  ],
+  "addons": [
+    "@storybook/addon-links",
+    "@storybook/addon-essentials",
+    "@storybook/addon-interactions"
+  ],
+  "framework": "@storybook/svelte",
+  "core": {
+    "builder": "@storybook/builder-vite",
+    "disableTelemetry": true
+  },
+  "svelteOptions": {
+    "preprocess": require("../svelte.config.cjs").preprocess
+  },
+  "features": {
+    "storyStoreV7": true
+  }
+}

.storybook/preview-head.html

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+<script>
+  window.global = window;
+</script>

.storybook/preview.cjs

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+export const parameters = {
+  actions: { argTypesRegex: "^on[A-Z].*" },
+  controls: {
+    matchers: {
+      color: /(background|color)$/i,
+      date: /Date$/,
+    },
+  },
+}