fix(api): revert auth/type regressions from standalone sync, keep email-in feature only

- Revert auth/dependencies.py to cookie+Bearer dual auth with str user IDs
- Add GET /auth/me/email-in-address endpoint for receipt email routing
- Update User model: add email_inbound_token, change id/store_id/user_id to str
- Update AuthService and UserResponse to use str user IDs
- Update route count test: 33 -> 34 routes
- Restore e2e test for email-in-address endpoint

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

src/cartsnitch_api/auth/dependencies.py

@@ -5,8 +5,6 @@ Sessions are verified by querying the shared sessions table directly.
 """
 
 from datetime import UTC, datetime
-from uuid import UUID
-
 from fastapi import Cookie, Depends, Header, HTTPException, Request, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from sqlalchemy import text
@@ -23,10 +21,10 @@ bearer_scheme = HTTPBearer(auto_error=False)
 SESSION_COOKIE_NAME = "better-auth.session_token"
 
 
-async def _validate_session_token(token: str, db: AsyncSession) -> UUID:
+async def _validate_session_token(token: str, db: AsyncSession) -> str:
     """Validate a Better-Auth session token against the sessions table.
 
-    Returns the user_id (as UUID) if the session is valid and not expired.
+    Returns the user_id (as str) if the session is valid and not expired.
     """
     result = await db.execute(
         text("SELECT user_id, expires_at FROM sessions WHERE token = :token"),
@@ -41,9 +39,6 @@ async def _validate_session_token(token: str, db: AsyncSession) -> UUID:
         )
 
     user_id, expires_at = row
-    # SQLite stores datetimes as ISO strings; parse if necessary
-    if isinstance(expires_at, str):
-        expires_at = datetime.fromisoformat(expires_at)
     if expires_at.tzinfo is None:
         # Treat naive datetimes as UTC
         expires_at = expires_at.replace(tzinfo=UTC)
@@ -54,14 +49,14 @@ async def _validate_session_token(token: str, db: AsyncSession) -> UUID:
             detail="Session expired",
         )
 
-    return UUID(str(user_id))
+    return str(user_id)
 
 
 async def get_current_user(
     request: Request,
     credentials: HTTPAuthorizationCredentials | None = Depends(bearer_scheme),
     db: AsyncSession = Depends(get_db),
-) -> UUID:
+) -> str:
     """Extract and validate the session token from cookie or Authorization header.
 
     Checks in order:

src/cartsnitch_api/auth/routes.py

@@ -5,15 +5,15 @@ the Better-Auth service (auth/). This router provides user profile
 endpoints that query our own user data from the shared database.
 """
 
-from uuid import UUID
-
 from fastapi import APIRouter, Depends, HTTPException, status
+from pydantic import BaseModel
+from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from cartsnitch_api.auth.dependencies import get_current_user
 from cartsnitch_api.database import get_db
+from cartsnitch_api.models import User
 from cartsnitch_api.schemas import (
-    EmailInAddressResponse,
     UpdateUserRequest,
     UserResponse,
 )
@@ -22,9 +22,14 @@ from cartsnitch_api.services.auth import AuthService
 router = APIRouter(prefix="/auth", tags=["auth"])
 
 
+class EmailInAddressResponse(BaseModel):
+    email_address: str
+    instructions: str
+
+
 @router.get("/me", response_model=UserResponse)
 async def get_me(
-    user_id: UUID = Depends(get_current_user),
+    user_id: str = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
     svc = AuthService(db)
@@ -39,7 +44,7 @@ async def get_me(
 @router.patch("/me", response_model=UserResponse)
 async def update_me(
     body: UpdateUserRequest,
-    user_id: UUID = Depends(get_current_user),
+    user_id: str = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
     svc = AuthService(db)
@@ -55,7 +60,7 @@ async def update_me(
 
 @router.delete("/me", status_code=status.HTTP_204_NO_CONTENT)
 async def delete_me(
-    user_id: UUID = Depends(get_current_user),
+    user_id: str = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
     svc = AuthService(db)
@@ -69,13 +74,19 @@ async def delete_me(
 
 @router.get("/me/email-in-address", response_model=EmailInAddressResponse)
 async def get_email_in_address(
-    user_id: UUID = Depends(get_current_user),
+    user_id: str = Depends(get_current_user),
     db: AsyncSession = Depends(get_db),
 ):
-    svc = AuthService(db)
-    try:
-        return await svc.get_email_in_address(user_id)
-    except LookupError:
+    result = await db.execute(select(User.email_inbound_token).where(User.id == user_id))
+    token = result.scalar_one_or_none()
+    if not token:
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND, detail="Email inbound token not found"
         ) from None
+    return EmailInAddressResponse(
+        email_address=f"receipts+{token}@receipts.cartsnitch.com",
+        instructions=(
+            "Forward your digital receipt emails to this address. "
+            "We currently support Meijer, Kroger, and Target receipt emails."
+        ),
+    )