Fix signup by using better-auth signUp and clearer register errors.

Route web registration through authClient.signUp.email, set explicit better-auth baseURL/secret for Docker, and harden the mobile register API with safeParse and readable validation messages.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/auth.ts

@@ -21,6 +21,8 @@ const authentikOrigin =
     : null;
 
 export const auth = betterAuth({
+  baseURL: process.env.BETTER_AUTH_URL,
+  secret: process.env.AUTH_SECRET,
   database: drizzleAdapter(db, {
     provider: "pg",
     schema: {