Enhancement: Allow delete_many to accept model instances in addition to IDs

[cofin]

Summary

The delete_many method on SQLAlchemyAsyncRepositoryService currently only accepts a list of primary key IDs. It would be helpful if it could also accept model instances and automatically extract their IDs.

Current Behavior

# This works
await service.delete_many([uuid1, uuid2, uuid3])

# This fails with: invalid input syntax for type uuid: "<Model object at 0x...>"
expired_tokens = await service.list(Model.expires_at < now)
await service.delete_many(list(expired_tokens))  # Passes model objects

Proposed Behavior

# Both should work
await service.delete_many([uuid1, uuid2, uuid3])  # IDs
await service.delete_many(list(expired_tokens))   # Model instances

Implementation Suggestion

In the service's delete_many method, check if items are model instances and extract their primary keys:

async def delete_many(
    self,
    item_ids: list[ModelT] | list[Any],
    ...
) -> Sequence[ModelT]:
    # If items are model instances, extract their IDs
    if item_ids and hasattr(item_ids[0], '__table__'):
        pk_col = inspect(self.model_type).primary_key[0].name
        item_ids = [getattr(item, pk_col) for item in item_ids]
    
    # ... rest of implementation

Use Case

This came up when implementing a cleanup job for expired tokens:

async def cleanup_expired_tokens(self) -> int:
    expired_tokens = await self.list(
        (Model.expires_at < current_time)
        | (Model.revoked_at.is_not(None) & Model.revoked_at < current_time)
    )
    
    if not expired_tokens:
        return 0
    
    # Currently requires this extra step:
    token_ids = [token.id for token in expired_tokens]
    await self.delete_many(token_ids)
    
    # Would be nicer to just do:
    # await self.delete_many(list(expired_tokens))
    
    return len(expired_tokens)

Additional Context

This would make the API more forgiving and consistent with patterns where you query models and then want to delete them in bulk.