Schedule source shouldn't delete existing schedules during startup

[danfimov]

taskiq-postgres version

0.9.0

Python version

Python 3.11 or lower

PostgreSQL driver

asyncpg

PostgreSQL version

All

What happened?

AsyncpgScheduleSource.startup() truncates ALL schedules — dynamic schedules added via add_schedule() can't survive a restart when mixed with label crons

Expected behavior

We should not touch at least dynamic schedules.

I see two potential solutions here:

• mark dynamic / static schedules in database and delete only static onces
• add flag to just skip all logic about truncate + recreate at once.

Steps to reproduce

Just call startup() + add schedule + restart broker with schedule source

Minimal code example

Relevant log output

Additional context

No response