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/nostr-tools/lib/esm/nip04.js

@@ -0,0 +1,40 @@
+// nip04.ts
+import { bytesToHex as bytesToHex2, randomBytes } from "@noble/hashes/utils";
+import { secp256k1 } from "@noble/curves/secp256k1";
+import { cbc } from "@noble/ciphers/aes";
+import { base64 } from "@scure/base";
+
+// utils.ts
+import { bytesToHex, hexToBytes } from "@noble/hashes/utils";
+var utf8Decoder = new TextDecoder("utf-8");
+var utf8Encoder = new TextEncoder();
+
+// nip04.ts
+function encrypt(secretKey, pubkey, text) {
+  const privkey = secretKey instanceof Uint8Array ? bytesToHex2(secretKey) : secretKey;
+  const key = secp256k1.getSharedSecret(privkey, "02" + pubkey);
+  const normalizedKey = getNormalizedX(key);
+  let iv = Uint8Array.from(randomBytes(16));
+  let plaintext = utf8Encoder.encode(text);
+  let ciphertext = cbc(normalizedKey, iv).encrypt(plaintext);
+  let ctb64 = base64.encode(new Uint8Array(ciphertext));
+  let ivb64 = base64.encode(new Uint8Array(iv.buffer));
+  return `${ctb64}?iv=${ivb64}`;
+}
+function decrypt(secretKey, pubkey, data) {
+  const privkey = secretKey instanceof Uint8Array ? bytesToHex2(secretKey) : secretKey;
+  let [ctb64, ivb64] = data.split("?iv=");
+  let key = secp256k1.getSharedSecret(privkey, "02" + pubkey);
+  let normalizedKey = getNormalizedX(key);
+  let iv = base64.decode(ivb64);
+  let ciphertext = base64.decode(ctb64);
+  let plaintext = cbc(normalizedKey, iv).decrypt(ciphertext);
+  return utf8Decoder.decode(plaintext);
+}
+function getNormalizedX(key) {
+  return key.slice(1, 33);
+}
+export {
+  decrypt,
+  encrypt
+};