Add SDK test evidence requirement to PR workflow

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Update the SDK PR workflow so contributors must provide testing evidence.

Current Behaviour

Many PRs may be submitted without tests or without explaining why tests are not included.

Expected Behaviour

Every SDK PR should state tests added, commands run, and whether CI passes.

Suggested Implementation

Update PR template, contribution docs, and examples of acceptable testing evidence.

Files or Areas Likely Affected

• .github/
• docs/
• README.md

Acceptance Criteria

• PR template requires tests added.
• PR template requires commands run.
• PR template requires CI status.
• No-test cases require justification.
• Examples of good testing evidence are included.
• README links to expectations.

Additional Notes

This makes testing expectations visible before review.