chore: update PR template

[pyrooka]

PR summary

Adds a checklist item and a dedicated section to the PR template asking contributors to provide evidence of a clean integration/examples test run when those tests are modified.

PR Checklist

• The commit message follows the Angular Commit Message Guidelines.
• Docs have been added / updated (for bug fixes / features)

Current vs new behavior

Previously, the PR template had no mention of integration/examples test evidence, so reviewers had to ask for it manually during review.

The template now includes:

• A checklist item reminding contributors to run integration/examples tests (if modified) and include a summary below.
• A new Integration / examples test evidence section where contributors paste a test run summary (e.g. final pass/fail counts), or write "N/A" if no integration tests or examples were changed.

Does this PR introduce a breaking change?

• Yes
• No

Integration / examples test evidence

N/A