MoreCast 2.0: Only Apply Selected Model when Data is Available

**As a** User Type/Persona
**I need** Feature/enhancement
**So That** Value, why is this needed, what does the user need to accomplish

Current State = problem when selecting HRDPS because it only goes out 2 days in advance, so will have null data when selected date range is >2 days in future:
Feature Request = one suggestion: only apply selected model when data is available

**Acceptance Criteria**
- [ ] Given (Context), When (action carried out), Then (expected outcome)
- [ ] Given (Context), When (action carried out), Then (expected outcome)

**Additional Context**
- enter text here
- enter text here

**Definition of Done**
https://github.com/bcgov/wps/wiki/Definition-of-Done

No files, tests, or entry points are named. Begin by locating the MoreCast model-selection and date-range handling, then trace how unavailable HRDPS data is represented. The acceptance criteria are still placeholders, so the expected behavior must be clarified before implementation can be verified.

Written by the indexing model from the issue text.