fix(registration): initialize diagnostics vars when optimize_poses=False

[EndingCredits]

Fixes UnboundLocalError in get_cleaned_poses when return_diagnostics=True and optimize_poses=False (the default).

Problem

outlier_edges, untestable_edges, and final_edge_errors were only defined inside the if optimize_poses: branch, but referenced unconditionally in the diagnostics dict.

Fix

Initialize sensible defaults in the else branch:

• outlier_edges = set() — no outlier removal performed
• untestable_edges — computed from edge_scores
• final_edge_errors = {} — no post-optimization residuals