feat: initialize markr nostr bookmark client

- Add project structure with TypeScript, React, and Vite
- Implement nostr authentication using browser extension (NIP-07)
- Add NIP-51 compliant bookmark fetching and display
- Create minimal UI with login and bookmark components
- Integrate applesauce-core and applesauce-react libraries
- Add responsive styling with dark/light mode support
- Include comprehensive README with setup instructions

This is a minimal MVP for a nostr bookmark client that allows users to
view their bookmarks according to NIP-51 specification.

node_modules/mdast-util-to-markdown/lib/util/check-bullet-other.js

@@ -0,0 +1,38 @@
+/**
+ * @import {Options, State} from 'mdast-util-to-markdown'
+ */
+
+import {checkBullet} from './check-bullet.js'
+
+/**
+ * @param {State} state
+ * @returns {Exclude<Options['bullet'], null | undefined>}
+ */
+export function checkBulletOther(state) {
+  const bullet = checkBullet(state)
+  const bulletOther = state.options.bulletOther
+
+  if (!bulletOther) {
+    return bullet === '*' ? '-' : '*'
+  }
+
+  if (bulletOther !== '*' && bulletOther !== '+' && bulletOther !== '-') {
+    throw new Error(
+      'Cannot serialize items with `' +
+        bulletOther +
+        '` for `options.bulletOther`, expected `*`, `+`, or `-`'
+    )
+  }
+
+  if (bulletOther === bullet) {
+    throw new Error(
+      'Expected `bullet` (`' +
+        bullet +
+        '`) and `bulletOther` (`' +
+        bulletOther +
+        '`) to be different'
+    )
+  }
+
+  return bulletOther
+}