Remove redundant copies and recomputation in the CLI analysis path

[annmoel]

• compute_radii now accepts a pre-computed EDT, and the pipeline computes it once per object crop instead of running distance_transform_edt twice (once for junction cleanup's temporary radius matrix, again for the final mask_radius output) whenever both extraction.junction_cleanup and extraction.mask_radius are enabled.
• Drop the second connected-components labeling pass in _analyze_single_object: it was mathematically equivalent to the _skeleton_has_no_branches check just above it (both detect "every component is a single isolated pixel"), so it ran scipy's labeling twice on the same skeleton for no reason.
• Fix compute_radii evaluating skeleton > 0 twice in the same expression instead of once.
• save_skeleton/save_radius pass copy=False to astype() so no full array copy happens when the array is already the target dtype (always true in practice, since lee94_thin and compute_radii already guarantee it).