Generates clear, structured pull request descriptions from branch diffs or commit lists. Creates summaries, change logs, test plans, breaking change notes, and related issue references. Use when the user asks for a PR description, needs to summarize changes for reviewers, or wants a test plan section for their PR. Turns a branch diff or commit list into a clear pull request description with summary, motivation, test plan, and breaking changes. Use when the user says "write a PR description", "summarize this diff for reviewers", or "generate a PR body".
