refactor(catalog): the unit's tables move into catalog/models

Channel, Subscription, Video, SearchFind, ExploredChannel and BlockedChannel (and LIVE_OR_UPCOMING)
leave app/models.py for app/catalog/models.py; app.tables registers them. The User↔Subscription
relationship names its other side as a type only. No schema change.

backend/app/sync/autotag.py

@@ -12,7 +12,7 @@ from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
 from app import logs, progress, sysconfig
-from app.models import Channel, Video
+from app.catalog.models import Channel, Video
 from app.reader import queries as reader_queries
 from app.reader import service as reader_service
 

backend/app/sync/explore.py

@@ -14,7 +14,7 @@ from sqlalchemy import delete, or_, select
 from sqlalchemy.orm import Session
 
 from app import logs, sysconfig
-from app.models import Channel, ExploredChannel, SearchFind, Subscription, Video
+from app.catalog.models import Channel, ExploredChannel, SearchFind, Subscription, Video
 from app.reader import queries as reader_queries
 from app.sync.videos import insert_stubs, stub_from_playlist_item, apply_video_details
 from app.youtube.client import YouTubeClient, YouTubeError, is_playlist_gone

backend/app/sync/maintenance.py

@@ -27,7 +27,7 @@ from sqlalchemy.orm import Session
 
 from app import logs, progress, quota, sysconfig
 from app.config import settings
-from app.models import Video
+from app.catalog.models import Video
 from app.reader import queries as reader_queries
 from app.notifications import create_notification
 from app.sync.runner import get_service_user

backend/app/sync/playlists.py

@@ -20,7 +20,8 @@ from sqlalchemy.pool import NullPool
 
 from app import logs, progress, quota
 from app.auth import has_read_scope
-from app.models import User, Video
+from app.models import User
+from app.catalog.models import Video
 from app.reader.models import Playlist, PlaylistItem
 from app.sync.playlist_merge import merge_plan
 from app.sync.runner import token_users

backend/app/sync/runner.py

@@ -16,7 +16,8 @@ from sqlalchemy.orm import Session
 
 from app import logs, progress, quota, sysconfig
 from app.db import SessionLocal
-from app.models import Channel, OAuthToken, Subscription, User
+from app.models import OAuthToken, User
+from app.catalog.models import Channel, Subscription
 from app.sync.explore import followed_channel
 from app.sync.subscriptions import import_subscriptions
 from app.sync.videos import (

backend/app/sync/subscriptions.py

@@ -7,7 +7,8 @@ from sqlalchemy import or_, select
 from sqlalchemy.orm import Session
 
 from app import logs
-from app.models import Channel, Subscription, User
+from app.models import User
+from app.catalog.models import Channel, Subscription
 from app.utils import normalize_description
 from app.youtube.client import YouTubeClient, YouTubeError, best_thumbnail
 

backend/app/sync/tagsuggest.py

@@ -23,7 +23,8 @@ from collections import Counter
 from sqlalchemy import select
 from sqlalchemy.orm import Session
 
-from app.models import Subscription, User
+from app.models import User
+from app.catalog.models import Subscription
 from app.reader.models import ChannelTag, Tag
 from app.userscope import owned_by
 

backend/app/sync/videos.py

@@ -12,7 +12,7 @@ from sqlalchemy.dialects.postgresql import insert as pg_insert
 from sqlalchemy.orm import Session
 
 from app import logs, progress, quota, sysconfig
-from app.models import LIVE_OR_UPCOMING, Channel, Video
+from app.catalog.models import LIVE_OR_UPCOMING, Channel, Video
 from app.titles import normalize_title
 from app.youtube.client import YouTubeClient, YouTubeError, best_thumbnail, is_playlist_gone
 from app.youtube.shorts import make_client, probe_is_short