fix: repair nightly pull request release notes

[vitormattos]

Consolidates the release workflow fixes into v0.6.6:

• repairs the nightly release-notes template from a clean base;
• prefers associated merged pull requests in nightly notes, deduplicated by PR number, with direct commits only as fallback;
• grants only read access to pull requests for nightly note resolution;
• updates the bundled release-tool to 0.10.2, which cascades public changelog history to newer stable branches and main, preserves changelog formatting, and marks history-only PRs/commits with [skip ci];
• strips GitHub authorization headers on cross-host artifact-storage redirects so post-merge release finalization can restore preparation artifacts reliably;
• bumps github-workflows to 0.6.6.