fix(optimize): log Broken Config Repair section under --debug (#904)

opt_fix_broken_configs was the only optimize task that never called
debug_operation_start, so `mo optimize --debug` printed the repaired
count to the terminal but the structured `=== Broken Config Repair ===`
block never reached mole_debug_session.log. That made it impossible to
audit which preference files were repaired and how.

Add the debug_operation_start / detail / risk-level block to match the
other optimize tasks, and log the repaired-file count after the run.