fix: align release changelog with template-repo format

[AndrewAltimit]

Summary

• Restructured the "Generate changelog" step to match template-repo's main-ci.yml pattern: flattened nested if/else for the previous-tag check vs changelog-empty check, added diagnostic echo messages ("Changelog generated successfully" / "No changelog generated")
• Moved GITHUB_TOKEN env declaration to step level (matching template convention)
• Removed unnecessary sed -i 's/^ //' whitespace stripping on the heredoc (YAML | already strips common indentation)
• Renamed heredoc delimiter from RELEASE_EOF to EOF and added id: release_notes to the step, matching template style

Test plan

• Trigger a manual release via workflow_dispatch with create_release: true and verify the "## What's Changed" section appears in the GitHub Release notes
• Verify the changelog lists merged PRs since the last tag

Generated with Claude Code

[github-actions]

Gemini AI Code Review

Issues (if any)

(none)

Previous Issues (for incremental reviews)

(none)

Suggestions (if any)

(none)

Notes

• Code restructuring aligns cleanly with the stated PR goals.
• Removing the sed command is correct; GitHub Actions YAML block scalars (|) automatically strip leading base indentation, making the manual whitespace stripping hack unnecessary.
• The flattened logic for handling an empty PREVIOUS_TAG or an empty CHANGELOG correctly manages the fallback states without nesting.

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Generated by Gemini AI (gemini-3.1-pro-preview). Supplementary to human reviews.

[github-actions]

Codex AI Code Review

Issues (if any)

(none)

Previous Issues (for incremental reviews)

(none)

Suggestions (if any)

(none)

Notes

• Verified the changed logic in .github/workflows/main-ci.yml:321, .github/workflows/main-ci.yml:338, and .github/workflows/main-ci.yml:352; no actionable regressions were identified in the provided diff.
• The flattened changelog control flow and removal of heredoc whitespace post-processing are behaviorally consistent with GitHub Actions YAML block-scalar handling.

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Generated by Codex AI (gpt-5.3-codex). Supplementary to human reviews.

[AndrewAltimit]

Review Response Agent (Iteration 1)

Status: No changes needed

Fixed Issues

• (none - both reviewers found zero issues)

Ignored Issues

• (none - no issues were raised)

Deferred to Human

• (nothing to defer)

Notes

• Gemini (gemini-3.1-pro-preview) and Codex (gpt-5.3-codex) both gave clean reviews with no issues, no suggestions, and positive notes confirming the correctness of the changes in .github/workflows/main-ci.yml
• Both reviewers confirmed the sed removal is correct since YAML block scalars (|) already strip leading base indentation
• Both confirmed the flattened changelog logic correctly handles fallback states

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The agent reviewed feedback but determined no code changes were required.