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/association.js

@@ -0,0 +1,33 @@
+/**
+ * @import {AssociationId} from '../types.js'
+ */
+
+import {decodeString} from 'micromark-util-decode-string'
+
+/**
+ * Get an identifier from an association to match it to others.
+ *
+ * Associations are nodes that match to something else through an ID:
+ * <https://github.com/syntax-tree/mdast#association>.
+ *
+ * The `label` of an association is the string value: character escapes and
+ * references work, and casing is intact.
+ * The `identifier` is used to match one association to another:
+ * controversially, character escapes and references don’t work in this
+ * matching: `&copy;` does not match `©`, and `\+` does not match `+`.
+ *
+ * But casing is ignored (and whitespace) is trimmed and collapsed: ` A\nb`
+ * matches `a b`.
+ * So, we do prefer the label when figuring out how we’re going to serialize:
+ * it has whitespace, casing, and we can ignore most useless character
+ * escapes and all character references.
+ *
+ * @type {AssociationId}
+ */
+export function association(node) {
+  if (node.label || !node.identifier) {
+    return node.label || ''
+  }
+
+  return decodeString(node.identifier)
+}