[Bug]: Pull request All commits diff stays stale after new commits

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/web

Steps to reproduce

1. Open a pull request in T3 Code.
2. Open its Code tab with All commits selected.
3. Push another commit to the pull request.
4. Wait for the pull request detail header to refresh.
5. Compare the header's updated state with the aggregate diff shown in All commits.

Expected behavior

When the pull request receives new commits, its detail data and All commits diff should refresh together and show one coherent snapshot.

Actual behavior

The detail header updates while the mounted aggregate diff remains on an older snapshot. Switching to an individual commit and back can expose the stale aggregate until it is explicitly refreshed.

Impact

Major degradation or frequent failure

Version or commit

main before #7167

Environment

Web and desktop clients using the shared pull request detail UI.

Logs or stack traces

Not applicable.

Screenshots, recordings, or supporting files

Not applicable.

Workaround

Explicitly refresh the pull request diff after new commits arrive.

Implemented in #7167.

Start in apps/web and trace the shared pull request detail UI used by the web and desktop clients. Compare the refresh path for the detail header with the mounted All commits aggregate diff, then verify that both display one coherent snapshot after new commits arrive. The issue notes that this was implemented in #7167.