Migrate Manager lock factory initialization to valkey-glide

## Objective

Update Manager server's lock factory to use valkey-glide client for distributed locking.

## Files to modify

- `src/ai/backend/manager/server.py` (lines 1414-1429)
- `init_lock_factory()` function

## Tasks

- [ ] Update RedisLock initialization to use valkey-glide client
- [ ] Update import statements
- [ ] Verify lock factory returns properly configured RedisLock instances
- [ ] Test distributed locking between manager instances

## Dependencies

Depends on: Migrate RedisLock implementation

## Related

Part of BA-2585 - Retire redis-py entirely

JIRA Issue: BA-3269