chore(release): categorize auto-generated release notes by label

[maatheusgois-dd]

Summary

• Adds .github/release.yml to configure GitHub's auto-generated release notes, so each future release shows a curated What's Changed section grouped by category (Features, Bug Fixes, Hardening & Validation, Dependencies, Documentation, Maintenance) instead of a flat uncategorized list.
• Style matches the headroom release feed (PR title + author mention + PR link, grouped under headed sections).

How it works

GitHub's generate_release_notes: true (already set in release.yml workflow) reads .github/release.yml and groups PRs by label:

• PRs labeled feature/enhancement → 🚀 Features
• PRs labeled bug/fix → 🐛 Bug Fixes
• PRs labeled hardening/validation/testing/ci → 🛠 Hardening & Validation
• PRs labeled dependencies → 📦 Dependencies (dependabot PRs show up here, with @dependabot[bot])
• PRs labeled ignore-for-release → excluded entirely
• Unlabeled PRs → a default Other Changes section (GitHub adds this automatically)

Validation

• Config file written and validated against the GitHub release notes schema.
• v0.1.30 release notes manually updated with curated content (this PR makes future releases automatic).
• Next release will auto-categorize once this merges and PRs carry the relevant labels.

Notes

• For the auto-categorization to show up, PRs need labels applied. Suggested label set to create (if not present): feature, enhancement, bug, fix, hardening, validation, testing, ci, dependencies, documentation, chore, maintenance, refactor, ignore-for-release.
• No code changes; config-only.

Co-authored-by: oh-my-pi https://omp.sh