Fix pyright type resolution for Pipeline parameter

[abrookins]

Fixes #678

Problem

Pyright could not resolve the Pipeline type in method signatures like save(), delete(), and expire(). While mypy correctly showed redis.asyncio.client.Pipeline[Any] | None, pyright showed just Unknown | None.

The root cause was the module aliasing pattern:

• aredis_om/async_redis.py imports redis.asyncio as redis
• model.py used redis.client.Pipeline for type hints via this alias
• Mypy could follow this aliasing, but pyright could not

Solution

• Import Pipeline directly from redis.asyncio.client in aredis_om/model/model.py
• Replace all redis.client.Pipeline type annotations with just Pipeline
• Add post-processing in make_sync.py to convert the import to from redis.client import Pipeline for the sync version

Verification

Before:

pyright: pipeline: Unknown | None

After:

pyright: pipeline: Pipeline[Unknown] | None
mypy: pipeline: redis.asyncio.client.Pipeline[Any] | None

Both type checkers now correctly identify the Pipeline type.