/ultrareview returns empty findings [] on large diff instead of error

Description

/ultrareview completed with a task notification status of completed and a findings payload of [], but on a diff that is clearly too large to have genuinely zero findings (170 files changed, 37k+ insertions).

Expected behaviour

Either return actual findings, or surface a clear error/partial-result indicator when the review cannot be completed (e.g. diff too large, timeout, internal failure).

Actual behaviour

Task status: completed
Findings returned: []
No error message or partial-result warning was shown.

Impact

Silent failure — the empty result looks indistinguishable from a genuine clean review, so the user has no signal that the review did not run.

Steps to reproduce

1. Run /ultrareview on a branch with a large diff against main (~170 files, ~37k lines).
2. Wait for the task notification.
3. Observe [] findings with completed status and no error.

Environment

• Claude Code CLI
• /ultrareview (no-arg form, local branch diff)