Add workflow summaries to release actions

[happyRip]

Summary

Add tables to make it easier to access useful information about the release actions.

Changes

• Add Workflow summary to release-*.yml actions.

Testing

Steps

Run the CI https://github.com/TheThingsNetwork/lorawan-stack/actions/runs/26949786579

Results

Regressions

n/a

Notes for Reviewers

Separating the summary into a separate job makes it visible before the full action finishes.

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.