bb pr diff <number> with --name-only

[zoldyzdk]

Parent PRD

#1

What to build

New bb pr diff [<number>] command that retrieves and displays the raw diff of a pull request from the Bitbucket API. In this slice, only the explicit PR number argument is supported (branch inference is added in a follow-up slice).

End-to-end: the user runs bb pr diff 42 and sees the unified diff output in their terminal. With --name-only, only the changed file paths are listed.

This requires:

• A new GetPullRequestDiff method in the API layer that calls GET /repositories/{workspace}/{repo}/pullrequests/{id}/diff and returns the raw diff string
• A new Cobra command (cmd/pr_diff.go) with --name-only flag
• Parsing the unified diff output to extract file names when --name-only is used

Acceptance criteria

• bb pr diff 42 outputs the raw unified diff from the Bitbucket API
• bb pr diff 42 --name-only outputs only the changed file paths (one per line)
• Clear error message if the PR number doesn't exist
• Workspace/repo resolution follows existing conventions (flags → config → git remote)
• The command accepts an optional positional argument (PR number); running without it shows a usage hint (branch inference comes in the next slice)

Blocked by

None - can start immediately

User stories addressed

• User story 5
• User story 7
• User story 25