feat(cursor-origin): List a pull request's files and commits

[wedamija]

Add support for listing the files and commits in a pull request. Origin does not provide blob SHAs for changed files, so sha is left empty.

[sentry]

Bug: The code uses direct dictionary access raw["patch"], which will raise a KeyError if the API response for a file (e.g., a binary file) omits the patch key.
_{Severity: HIGH}

Suggested Fix

Use the safe .get() method to access the patch key, for example: raw.get("patch"). This will return None if the key is absent, preventing a KeyError and ensuring more robust handling of API responses.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: src/scm/providers/cursor_origin/provider.py#L756

Potential issue: The `map_pull_request_file` function directly accesses the `patch` key
from the API response dictionary using `raw["patch"]`. This will raise a `KeyError` if
the key is not present in the response. Based on similar APIs like GitHub's, the `patch`
key is often omitted for binary files or very large diffs. Since this function interacts
with a new, unproven API endpoint, assuming the `patch` key is always present is risky
and likely to cause failures when processing pull requests containing such files. The
same unsafe access pattern is also present in the `map_commit_file` function.

Also affects:

• src/scm/providers/cursor_origin/provider.py:745

_{Did we get this right? 👍 / 👎 to inform future reviews.}