Improve cross-site customer signup and login membership.

Same-password register joins silently; mismatched password explains the existing Meshkee account; login/OTP with domain attaches business membership.

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

src/auth/dto/login-otp.dto.ts

@@ -1,4 +1,4 @@
-import { IsString, Length, Matches } from 'class-validator';
+import { IsOptional, IsString, Length, Matches } from 'class-validator';
 
 export class LoginOtpDto {
   @IsString()
@@ -11,4 +11,9 @@ export class LoginOtpDto {
   @Length(6, 6)
   @Matches(/^\d{6}$/, { message: 'code must be a 6-digit number' })
   code!: string;
+
+  /** Website apex — when set, attaches customer membership for that tenant on successful OTP login. */
+  @IsOptional()
+  @IsString()
+  domain?: string;
 }

src/auth/dto/login.dto.ts

@@ -1,4 +1,4 @@
-import { IsString, Matches, MinLength } from 'class-validator';
+import { IsOptional, IsString, Matches, MinLength } from 'class-validator';
 
 export class LoginDto {
   @IsString()
@@ -10,4 +10,9 @@ export class LoginDto {
   @IsString()
   @MinLength(8)
   password!: string;
+
+  /** Website apex — when set, attaches customer membership for that tenant on successful login. */
+  @IsOptional()
+  @IsString()
+  domain?: string;
 }