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/applesauce-content/dist/helpers/regexp.js

@@ -0,0 +1,48 @@
+export const Expressions = {
+    get url() {
+        return /(?:https?|wss?|ircs?|s?ftp):\/\/([a-zA-Z0-9\.\-]+\.[a-zA-Z]+(?::\d+)?)([\/\?#][\p{L}\p{N}\p{M}&\.-\/\?=#\-@%\+_,:!~*]*)?/gu;
+    },
+    get link() {
+        return /https?:\/\/([a-zA-Z0-9\.\-]+\.[a-zA-Z]+(?::\d+)?)([\/\?#][\p{L}\p{N}\p{M}&\.-\/\?=#\-@%\+_,:!~*]*)?/gu;
+    },
+    get cashu() {
+        return /(?:cashu:\/{0,2})?(cashu(?:A|B)[A-Za-z0-9_-]{100,}={0,3})/gi;
+    },
+    get nostrLink() {
+        return /(?:nostr:)?((npub|note|nprofile|nevent|naddr)1[qpzry9x8gf2tvdw0s3jn54khce6mua7l]{58,})/gi;
+    },
+    get emoji() {
+        return /:([a-zA-Z0-9_-]+):/gi;
+    },
+    get hashtag() {
+        // NOTE: cant use \b here because it uses \w which only matches latin letters
+        return /(?<=^|[^\p{L}#\/])#([\p{L}\p{N}\p{M}]+)(?=\p{Z}|$|\s)/gu;
+    },
+    get lightning() {
+        return /(?:lightning:)?(LNBC[A-Za-z0-9]+)/gim;
+    },
+};
+/** A list of Regular Expressions that match tokens surrounded by whitespace to avoid matching in URLs */
+export const Tokens = {
+    get url() {
+        return Expressions.url;
+    },
+    get link() {
+        return Expressions.link;
+    },
+    get cashu() {
+        return new RegExp(`(?<=^|\\s)${Expressions.cashu.source}`, "gi");
+    },
+    get nostrLink() {
+        return new RegExp(`(?<=^|\\s)${Expressions.nostrLink.source}`, "gi");
+    },
+    get emoji() {
+        return Expressions.emoji;
+    },
+    get hashtag() {
+        return Expressions.hashtag;
+    },
+    get lightning() {
+        return new RegExp(`(?<=^|\\s)${Expressions.lightning.source}`, "gim");
+    },
+};