refactor(core): the core's owner filters go through userscope, each held by a second account

Tokens, notifications, quota, debug sessions and the reset-link burn filtered
their owner inline. Ten of the fifteen filters had no test that noticed one
going missing; each now has a test where another account's rows must not
count, show or change.

backend/app/routes/auth.py

@@ -16,6 +16,7 @@ from sqlalchemy import select, update
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
+from app.userscope import owned_by
 from app import apitokens
 from app import email as email_mod
 from app import logs
@@ -1124,7 +1125,7 @@ def password_reset_confirm(body: TokenPasswordIn, db: Session = Depends(get_db))
     # Burn any other outstanding reset tokens for this user.
     for row in db.execute(
         select(AuthToken).where(
-            AuthToken.user_id == user.id,
+            owned_by(AuthToken.user_id, user),
             AuthToken.kind.in_(_PASSWORD_TOKEN_KINDS),
             AuthToken.used_at.is_(None),
         )

backend/app/routes/debug_sessions.py

@@ -18,6 +18,7 @@ from sqlalchemy import select
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm import Session
 
+from app.userscope import owned_by
 from app import audit, debugsession, logs, logsink
 from app.audit import AuditAction
 from app.auth import current_user
@@ -95,7 +96,7 @@ def stop_session(
 def list_sessions(user: User = Depends(current_user), db: Session = Depends(get_db)) -> dict:
     sessions = db.scalars(
         select(DebugSession)
-        .where(DebugSession.user_id == user.id)
+        .where(owned_by(DebugSession.user_id, user))
         .order_by(DebugSession.started_at.desc())
         .limit(LIST_MAX)
     ).all()

backend/app/routes/notifications.py

@@ -5,6 +5,7 @@ from fastapi import APIRouter, Depends, Query
 from sqlalchemy import func, select, update
 from sqlalchemy.orm import Session
 
+from app.userscope import owned_by
 from app.auth import current_user
 from app.db import get_db
 from app.models import Notification, User
@@ -36,7 +37,7 @@ def list_notifications(
     user: User = Depends(current_user),
     db: Session = Depends(get_db),
 ) -> dict:
-    where = [Notification.user_id == user.id]
+    where = [owned_by(Notification.user_id, user)]
     if not include_dismissed:
         where.append(Notification.dismissed.is_(False))
     total = db.scalar(select(func.count()).select_from(Notification).where(*where)) or 0
@@ -61,7 +62,7 @@ def unread_count(user: User = Depends(current_user), db: Session = Depends(get_d
         select(func.count())
         .select_from(Notification)
         .where(
-            Notification.user_id == user.id,
+            owned_by(Notification.user_id, user),
             Notification.read.is_(False),
             Notification.dismissed.is_(False),
         )
@@ -86,7 +87,7 @@ def mark_read(
 def mark_all_read(user: User = Depends(current_user), db: Session = Depends(get_db)) -> dict:
     db.execute(
         update(Notification)
-        .where(Notification.user_id == user.id, Notification.read.is_(False))
+        .where(owned_by(Notification.user_id, user), Notification.read.is_(False))
         .values(read=True)
     )
     db.commit()
@@ -113,7 +114,7 @@ def clear_all(user: User = Depends(current_user), db: Session = Depends(get_db))
     """Dismiss every (still-visible) notification for this user."""
     db.execute(
         update(Notification)
-        .where(Notification.user_id == user.id, Notification.dismissed.is_(False))
+        .where(owned_by(Notification.user_id, user), Notification.dismissed.is_(False))
         .values(dismissed=True, read=True)
     )
     db.commit()

backend/app/routes/quota.py

@@ -10,6 +10,7 @@ from fastapi import APIRouter, Depends, Query
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
+from app.userscope import owned_by
 from app import quota
 from app.auth import admin_user, current_user
 from app.db import get_db
@@ -27,7 +28,7 @@ def _sum(db: Session, *conds) -> int:
 @router.get("/my-usage")
 def my_usage(user: User = Depends(current_user), db: Session = Depends(get_db)) -> dict:
     now = datetime.now(timezone.utc)
-    mine = QuotaEvent.user_id == user.id
+    mine = owned_by(QuotaEvent.user_id, user)
     by_action = {
         action: int(units)
         for action, units in db.execute(

backend/app/routes/tokens.py

@@ -16,6 +16,7 @@ from pydantic import BaseModel, Field
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
+from app.userscope import owned_by
 from app import apitokens, audit
 from app.apitokens import GRANT_COLUMNS, Right
 from app.audit import AuditAction
@@ -86,7 +87,7 @@ def _serialize(db: Session, token: ApiToken) -> dict:
 @router.get("")
 def list_tokens(user: User = Depends(current_user), db: Session = Depends(get_db)) -> list[dict]:
     tokens = (
-        db.execute(select(ApiToken).where(ApiToken.user_id == user.id).order_by(ApiToken.id))
+        db.execute(select(ApiToken).where(owned_by(ApiToken.user_id, user)).order_by(ApiToken.id))
         .scalars()
         .all()
     )
@@ -134,7 +135,7 @@ def create_token(
     if (epoch or 0) != (user.session_epoch or 0):
         raise refused(401, "not_authenticated")
     count = db.execute(
-        select(func.count(ApiToken.id)).where(ApiToken.user_id == user.id)
+        select(func.count(ApiToken.id)).where(owned_by(ApiToken.user_id, user))
     ).scalar_one()
     if count >= MAX_TOKENS:
         raise refused(409, "api_token_limit", limit=MAX_TOKENS)