Extract groombook/api from monorepo with CI workflow

- Add source code from apps/api
- Add packages/db and packages/types workspace dependencies
- Add GitHub Actions CI workflow (lint, typecheck, test, docker)
- Generate pnpm-lock.yaml
- Add .gitignore

Co-Authored-By: Paperclip <noreply@paperclip.ing>

packages/db/src/crypto.ts

@@ -0,0 +1,94 @@
+import { createCipheriv, createDecipheriv, randomBytes, scryptSync } from "node:crypto";
+
+const ALGORITHM = "aes-256-gcm";
+const IV_LENGTH = 12; // 96-bit IV for GCM
+const AUTH_TAG_LENGTH = 16; // 128-bit auth tag
+const SALT_LENGTH = 16;
+
+/**
+ * Derives a 32-byte key from BETTER_AUTH_SECRET using scrypt.
+ * A unique random salt is generated per encryptSecret() call and prepended to the output.
+ */
+function deriveKey(secret: string, salt: Buffer): Buffer {
+  return scryptSync(secret, salt, 32);
+}
+
+/**
+ * Encrypts a plaintext string using AES-256-GCM.
+ * Returns a base64-encoded string in the format: salt:iv:ciphertext:authTag
+ */
+export function encryptSecret(plaintext: string): string {
+  const secret = process.env.BETTER_AUTH_SECRET;
+  if (!secret) {
+    throw new Error("BETTER_AUTH_SECRET environment variable is required");
+  }
+
+  const salt = randomBytes(SALT_LENGTH);
+  const key = deriveKey(secret, salt);
+  const iv = randomBytes(IV_LENGTH);
+
+  const cipher = createCipheriv(ALGORITHM, key, iv, {
+    authTagLength: AUTH_TAG_LENGTH,
+  });
+
+  let ciphertext = cipher.update(plaintext, "utf8");
+  ciphertext = Buffer.concat([ciphertext, cipher.final()]);
+
+  const authTag = cipher.getAuthTag();
+
+  // Format: base64(salt):base64(iv):base64(ciphertext):base64(authTag)
+  return [
+    salt.toString("base64"),
+    iv.toString("base64"),
+    ciphertext.toString("base64"),
+    authTag.toString("base64"),
+  ].join(":");
+}
+
+/**
+ * Decrypts a ciphertext string produced by encryptSecret.
+ * Supports both new format (salt:iv:ciphertext:authTag) and legacy format (iv:ciphertext:authTag).
+ */
+export function decryptSecret(encrypted: string): string {
+  const secret = process.env.BETTER_AUTH_SECRET;
+  if (!secret) {
+    throw new Error("BETTER_AUTH_SECRET environment variable is required");
+  }
+
+  const parts = encrypted.split(":");
+
+  let salt: Buffer;
+  let iv: Buffer;
+  let ciphertext: Buffer;
+  let authTag: Buffer;
+
+  if (parts.length === 4) {
+    // New format: salt:iv:ciphertext:authTag
+    salt = Buffer.from(parts[0]!, "base64");
+    iv = Buffer.from(parts[1]!, "base64");
+    ciphertext = Buffer.from(parts[2]!, "base64");
+    authTag = Buffer.from(parts[3]!, "base64");
+  } else if (parts.length === 3) {
+    // Legacy format: iv:ciphertext:authTag — use fixed package salt
+    salt = scryptSync("groombook-auth-provider-config", "", SALT_LENGTH);
+    iv = Buffer.from(parts[0]!, "base64");
+    ciphertext = Buffer.from(parts[1]!, "base64");
+    authTag = Buffer.from(parts[2]!, "base64");
+  } else {
+    throw new Error(
+      "Invalid encrypted value format: expected salt:iv:ciphertext:authTag or iv:ciphertext:authTag"
+    );
+  }
+
+  const key = deriveKey(secret, salt);
+
+  const decipher = createDecipheriv(ALGORITHM, key, iv, {
+    authTagLength: AUTH_TAG_LENGTH,
+  });
+  decipher.setAuthTag(authTag);
+
+  let plaintext = decipher.update(ciphertext);
+  plaintext = Buffer.concat([plaintext, decipher.final()]);
+
+  return plaintext.toString("utf8");
+}