Revert "[verified] feat: add external calendar subscriptions"

This reverts commit 583b6a8a9d.

backend/backup/service.py

@@ -19,7 +19,6 @@ from backend.models import (
     BackupImport,
     BackupImportEntity,
     BackupPreflight,
-    CalendarSubscription,
     Countdown,
     Folder,
     Habit,
@@ -66,7 +65,6 @@ ENTITY_MODELS = {
     "habit_pauses": HabitPause,
     "countdowns": Countdown,
     "memos": Memo,
-    "calendar_subscriptions": CalendarSubscription,
     "attachments": Attachment,
 }
 RELATIONS = {
@@ -394,9 +392,6 @@ def _validate_recurrence_graph(parsed: ParsedArchive) -> None:
 
 def validate_archive(parsed: ParsedArchive) -> None:
     unknown = set(parsed.entities) - set(ENTITY_MODELS)
-    # Calendar subscriptions were introduced after backup v2. Treat their
-    # absence as an empty collection so archives from older Dodo releases remain restorable.
-    parsed.entities.setdefault("calendar_subscriptions", [])
     missing = set(ENTITY_MODELS) - set(parsed.entities)
     if unknown:
         raise backup_error("backup_entity_unknown", "备份包含未知实体")
@@ -616,16 +611,7 @@ async def restore_v2(
             await db.execute(delete(HabitPause).where(
                 HabitPause.habit_id.in_(select(Habit.id).where(Habit.user_id == user.id))
             ))
-            for model in (
-                Attachment,
-                CalendarSubscription,
-                Memo,
-                Countdown,
-                Task,
-                Habit,
-                TaskList,
-                Folder,
-            ):
+            for model in (Attachment, Memo, Countdown, Task, Habit, TaskList, Folder):
                 await db.execute(delete(model).where(model.user_id == user.id))
             await db.execute(delete(BackupImportEntity).where(BackupImportEntity.user_id == user.id))
             await db.execute(delete(BackupImport).where(BackupImport.user_id == user.id))