refactor(claude/commands): clarify PR description expectations in commit-push-pr

The previous instructions were vague about what the PR description should
contain, leading to redundant commit lists in PR bodies. Now explicitly
instructs the agent to use git diff alongside git log, write a cohesive
summary of purpose and impact, and avoid listing commits since the PR
already shows those.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

claude/commands/commit-push-pr.md

@@ -32,11 +32,14 @@ Based on the above changes:
    base the commit message solely on those changes. Do NOT stage additional
    files. Otherwise, stage all relevant changes.
 4. Push the branch to origin
-5. Create a pull request using `gh pr create`. The PR description should cover
-   all commits on the branch since main/master (use `git log` to review them),
-   not just the latest commit. Check for a PR template at
-   `.github/PULL_REQUEST_TEMPLATE.md` — if one exists, use it as the base for
-   the PR body and fill in the sections appropriately.
+5. Create a pull request using `gh pr create`. Use `git log` and
+   `git diff main...HEAD` (or master) to understand all changes on the branch.
+   The PR description should clearly explain *what* changed and *why*, covering
+   the full scope of changes since main/master. Do NOT include a list of
+   commits — the PR already shows those. Focus on a cohesive summary that
+   helps a reviewer understand the purpose and impact of the changes. Check for
+   a PR template at `.github/PULL_REQUEST_TEMPLATE.md` — if one exists, use it
+   as the base for the PR body and fill in the sections appropriately.
 6. You have the capability to call multiple tools in a single response. You MUST
    do all of the above in a single message. Do not use any other tools or do
    anything else. Do not send any other text or messages besides these tool