Add GitHub Pull Request template

[Copilot]

Summary

What changed?

• Updated the PR template markdown content to improve clarity and completeness of required sections.

Why is this change needed?

• PR descriptions were frequently missing key context, slowing reviews and increasing back-and-forth.
• The AI disclosure section is required; this update makes it harder to skip and easier to complete consistently.

Issues / work items

• Resolves: N/A
• Related: N/A

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Project checklist

• Release notes are not required for the next release
  • Otherwise: Notes added to release_notes.md
• Backport is not required
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• All required tests have been added/updated (unit tests, E2E tests)
• Breaking change? No
  • If yes:
    • Impact: N/A
    • Migration guidance: N/A

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AI-assisted code disclosure (required)

Was an AI tool used? (select one)

• No
• Yes, AI helped write parts of this PR (e.g., GitHub Copilot)
• Yes, an AI agent generated most of this PR

If AI was used:

• Tool(s): GitHub Copilot
• AI-assisted areas/files: PR template markdown (this file)
• What you changed after AI output: Reviewed wording for accuracy and adjusted checklist selections.

AI verification (required if AI was used):

• I understand the code and can explain it
• I verified referenced APIs/types exist and are correct
• I reviewed edge cases/failure paths (timeouts, retries, cancellation, exceptions)
• I reviewed concurrency/async behavior
• I checked for unintended breaking or behavior changes

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Testing

Automated tests

• Result: Passed (N/A – documentation/template-only change)

Manual validation (only if runtime/behavior changed)

• Environment (OS, .NET version, components): N/A
• Steps + observed results:
  1. Previewed the rendered markdown to confirm formatting.
  2. Verified all sections are complete and scannable for reviewers.
  3. N/A
• Evidence (optional): N/A

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Notes for reviewers

• This PR only updates the PR template.

[Copilot]

Pull request overview

This PR adds a comprehensive pull request template for the durabletask-dotnet repository to standardize PR submissions. The template enforces consistent structure and ensures contributors address critical aspects like testing, AI code disclosure, breaking changes, and manual validation before submission.

Key Changes

• Added .github/PULL_REQUEST_TEMPLATE.md with structured sections covering summary, change type, AI disclosure requirements, testing expectations (both automated and manual), compatibility considerations, and author review checklist
• Included DurableTask-specific validation scenarios for manual testing (orchestration behavior, activity execution, failure handling, cancellation flows, timers, concurrency, and backward compatibility)
• Required AI verification checklist ensures contributors using AI tools verify correctness, edge cases, concurrency behavior, and unintended changes