Add SDK evaluation-readiness checklist

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Add an evaluation-readiness checklist for GrantFox contributors working on SDK issues.

Current Behaviour

Contributors may assume a merged PR guarantees payment approval.

Expected Behaviour

The repo should clearly explain that merged PRs still need to satisfy issue requirements, tests, CI, and evaluation standards.

Suggested Implementation

Create a checklist covering requirements, tests, CI, documentation, meaningful implementation, and honest self-review before payment period.

Files or Areas Likely Affected

• docs/
• README.md
• .github/

Acceptance Criteria

• Evaluation-readiness checklist is added.
• Checklist states that merge does not guarantee approval.
• Testing and CI expectations are included.
• Acceptance criteria review is included.
• Self-review guidance is included.
• README links to the checklist.

Additional Notes

This aligns contributor expectations before the payment period.