Wrong Encoding or Font for Non-latin Characters when Generated Social Feature Images

### Impacted plugin

Social

### Quick summary

The Social Image Generator doesn't show non-Latin characters correctly in the generated images:


### Steps to reproduce

1. Create a post
2. Add a non-Latin text to the title, try: शुभ प्रभात
3. Go to Jetpack > Social Image Generator > Enable Social Image
4. Notice that the overlay text is just squares or lines

### Site owner impact

Between 20% and 60% of the total website/platform users

### Severity

Minor

### What other impact(s) does this issue have?

_No response_

### If a workaround is available, please outline it here.

The severity is reduced, and the workaround is just not to use the feature.
This said, we do have this open Bug which may still affect the experience: #38975

### Platform (Simple and/or Atomic)

Atomic

Start with the Jetpack > Social Image Generator flow described in the issue and reproduce it using the Hindi title “शुभ प्रभात” on an Atomic site. Trace how the overlay text is rendered and how its font or encoding is selected. Done means non-Latin characters appear correctly in generated social images without breaking the existing Latin-text output.

Written by the indexing model from the issue text.