docs: add research brief on GitHub issue/PR/project workflows#85

jlevy merged 2 commits into

claude/external-issue-linking-1rGfbjlevy/tbd:claude/external-issue-linking-1rGfbfrom

claude/merge-issue-linking-research-pOYMkjlevy/tbd:claude/merge-issue-linking-research-pOYMkCopy head branch name to clipboard