feat: add invite code feature (create, validate, referrer tracking)

backend/src/v1/auth/schemas.py

@@ -1,13 +1,21 @@
 from __future__ import annotations
 
-from pydantic import BaseModel, EmailStr, Field
+from pydantic import BaseModel, ConfigDict, EmailStr, Field
 
 
 class VerificationCreateRequest(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
     username: str = Field(min_length=3, max_length=30)
     email: EmailStr
     password: str = Field(min_length=6)
     redirect_to: str | None = None
+    invite_code: str | None = Field(
+        default=None,
+        min_length=8,
+        max_length=8,
+        pattern=r"^[ABCDEFGHJKMNPQRSTUVWXYZ23456789]{8}$",
+    )
 
 
 class VerificationResendRequest(BaseModel):
@@ -65,7 +73,3 @@ class PasswordResetConfirmRequest(BaseModel):
     email: EmailStr
     token: str = Field(pattern=r"^\d{6}$")
     new_password: str = Field(min_length=6)
-
-
-class PasswordResetResponse(BaseModel):
-    message: str = "Password reset email sent"