### Check for existing issues

- [x] I searched existing issues and PRs and found no recurring availability schedule for provider credentials or deployments

### The Feature

Allow named provider credentials to define recurring availability through `credential_info.availability_schedule`. Every deployment using `litellm_credential_name` inherits that schedule. Deployments with inline credentials can set the same field in `model_info`

```yaml credential_list: - credential_name: discounted-provider credential_values: api_key: os.environ/PROVIDER_API_KEY credential_info: availability_schedule: timezone: America/Los_Angeles windows: - days: [mon, tue, wed, thu, fri, sat, sun] start: "00:00" end: "06:00" ```

`start` is inclusive and `end` is exclusive. Overnight windows are supported. Missing schedules preserve current behavior

### Motivation, pitch

Some providers offer lower prices or reserved capacity only during defined off-peak windows. LiteLLM should route to those credentials during the window and automatically use other deployments outside it without external cron jobs or proxy restarts

### Proposed impl…