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

VideoState, Playlist, PlaylistItem, SavedView, ComfortPin, Tag and ChannelTag leave app/models.py
for app/reader/models.py; app.tables registers them. No schema change.

backend/app/sync/autotag.py

@@ -12,7 +12,8 @@ from sqlalchemy import and_, exists, func, select
 from sqlalchemy.orm import Session
 
 from app import logs, progress, sysconfig
-from app.models import Channel, ChannelTag, SavedView, Tag, Video
+from app.models import Channel, Video
+from app.reader.models import ChannelTag, SavedView, Tag
 
 log = logs.get_logger(__name__)
 

backend/app/sync/explore.py

@@ -14,15 +14,8 @@ from sqlalchemy import delete, or_, select
 from sqlalchemy.orm import Session
 
 from app import logs, sysconfig
-from app.models import (
-    Channel,
-    ExploredChannel,
-    PlaylistItem,
-    SearchFind,
-    Subscription,
-    Video,
-    VideoState,
-)
+from app.models import Channel, ExploredChannel, SearchFind, Subscription, Video
+from app.reader.models import PlaylistItem, VideoState
 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 +27,8 @@ from sqlalchemy.orm import Session
 
 from app import logs, progress, quota, sysconfig
 from app.config import settings
-from app.models import Playlist, PlaylistItem, Video
+from app.models import Video
+from app.reader.models import Playlist, PlaylistItem
 from app.notifications import create_notification
 from app.sync.runner import get_service_user
 from app.sync.videos import apply_video_details, parse_dt

backend/app/sync/playlists.py

@@ -21,7 +21,8 @@ from sqlalchemy.pool import NullPool
 
 from app import logs, progress, quota
 from app.auth import has_read_scope
-from app.models import Channel, Playlist, PlaylistItem, User, Video
+from app.models import Channel, User, Video
+from app.reader.models import Playlist, PlaylistItem
 from app.sync.playlist_merge import merge_plan
 from app.sync.runner import token_users
 from app.sync.subscriptions import blank_listing, refuse_blank_listing, vanished

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 ChannelTag, Subscription, Tag, User
+from app.models import Subscription, User
+from app.reader.models import ChannelTag, Tag
 
 # A user tag needs at least this many manually-tagged example channels before we trust its
 # profile — fewer is noise (one gaming-cooking channel shouldn't make "cooking" mean "gaming").