Implement standardized PULL_REQUEST_TEMPLATE.md for SWoC'26

[Nitya-003]

🔗 Linked Issue

Closes #34

🛠 Type of Change

• Documentation - Added PR template to streamline SWoC contributions.

📝 Summary

This PR introduces a standardized .github/pull_request_template.md to ensure high-quality contributions during SWoC'26.

Key inclusions:

• Transform Lifecycle Checklist: Ensures contributors follow the BaseTransform and Pydantic normalization standards.
• Testing Evidence: Requires logs from make dev to verify builds.
• Ethical Review: A mandatory checkbox to maintain the project's commitment to ethical OSINT.
• Visuals Section: Specifically for UI/Dashboard enhancements.

🧪 Testing Evidence

Verified the template by checking the file structure. The file is located at .github/pull_request_template.md, which is the standard GitHub path for auto-population.

🛡 Ethical Review

• I confirm this contribution aligns with SpectraGraph’s Ethics & Safety Guidelines.