ci: Improved generated release patch notes

[DylanDevelops]

Pull Request Checklist

• I have read and followed the contribution guidelines.
• My pull request targets the main branch of tmpo.
• I have tested these changes locally on my machine.

Closes #156

Description

This pull request introduces a new automated release notes workflow and improves the PR labeling and release process. The changes remove the old git-cliff-based changelog generation in favor of GitHub's native release notes API, add a workflow for automatic PR labeling based on conventional commit titles, and update documentation to reflect the new process.

Release automation and changelog generation:

• Replaces the git-cliff-based changelog system by removing cliff.toml and switching the release workflow to use GitHub's releases/generate-notes API for generating release notes. The new process also strips conventional commit prefixes for cleaner notes. (.github/workflows/release.yml, cliff.toml) [1] [2]
• Adds a detailed changelog configuration in .github/release.yml to group PRs in release notes by type (e.g., Features, Bug Fixes, Performance, etc.), and to exclude PRs with the ignore-for-release label or authored by bots.

Pull request labeling and documentation:

• Introduces a new workflow (.github/workflows/label-prs.yml) that automatically applies a type: label to PRs based on their conventional commit-style title, ensuring consistent categorization for release notes.
• Updates CONTRIBUTING.md to require conventional-commit-style PR titles and documents the new release process, including how release notes are generated and how to preview them.

Label standardization:

• Updates Dependabot and GitHub Actions PR labels in .github/dependabot.yml to use the new type: dependencies label, aligning with the new labeling convention.