This commit merges the interception and soft-eviction logic from daily_limit.py into volc_limit_sync.py.
It enables a unified solution where:
1. Running the script directly starts the sync daemon.
2. Importing 'proxy_handler_instance' provides the LiteLLM callback handler.
The handler now respects dynamic limits synced to Redis.
This commit introduces a dual-layer rate limiting system:
1. volc_limit_sync.py: A daemon that adaptively syncs Volcengine API balances to Redis based on traffic and safety margins.
2. daily_limit.py: Updated to enforce dynamic limits by checking Redis (Current Usage + Remaining Balance) and handling soft evictions.
kim