feat(skill): add make-repo-contribution skill

Adds a new skill to help AI agents follow repository contribution guidelines
when creating issues, commits, branches, and pull requests.

Includes:
- SKILL.md with comprehensive instructions
- Issue template for when none exists in repo
- PR template for when none exists in repo

skills/make-repo-contribution/assets/pr-template.md

@@ -0,0 +1,36 @@
+# <!-- Provide a concise, descriptive title for the pull request -->
+
+## Summary
+
+<!-- Provide a three to four sentence description of what this PR accomplishes. -->
+
+## Background
+
+<!-- Explain why this change is needed. Include:
+- The problem being solved or feature being added
+- Link to related issues (use "Closes #123" to auto-close)
+- Any relevant context or discussions
+-->
+
+## Changes
+
+<!-- List the changes being made, logically grouped. Include:
+- Files added, modified, or deleted
+- Key code changes with brief explanations
+- Any architectural or design decisions made
+-->
+
+## Testing
+
+<!-- Describe how the changes were validated:
+- Commands run (e.g., `npm run build`, `npm run validate`)
+- Manual testing performed
+- Edge cases considered
+-->
+
+## Additional Notes
+
+<!-- Include any of the following if relevant:
+- Breaking changes or migration steps
+- Highlights for human reviewers
+-->