add keycrow feature ideas, exclude features/ from biome

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

features/keycrow/src/utils/encryption.ts

@@ -0,0 +1,33 @@
+import CryptoJS from 'crypto-js';
+import { config } from '../config';
+
+export class EncryptionService {
+  private static instance: EncryptionService;
+  private readonly key: string;
+
+  private constructor() {
+    this.key = config.encryption.key;
+  }
+
+  static getInstance(): EncryptionService {
+    if (!EncryptionService.instance) {
+      EncryptionService.instance = new EncryptionService();
+    }
+    return EncryptionService.instance;
+  }
+
+  encrypt(plainText: string): string {
+    return CryptoJS.AES.encrypt(plainText, this.key).toString();
+  }
+
+  decrypt(cipherText: string): string {
+    const bytes = CryptoJS.AES.decrypt(cipherText, this.key);
+    return bytes.toString(CryptoJS.enc.Utf8);
+  }
+
+  hash(data: string): string {
+    return CryptoJS.SHA256(data).toString();
+  }
+}
+
+export const encryptionService = EncryptionService.getInstance();