fix: Pass 0b filter — skip obligations whose parent already has pass0b controls

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

control-pipeline/services/decomposition_pass.py

@@ -3543,12 +3543,12 @@ class DecompositionPass:
             FROM obligation_candidates oc
             JOIN canonical_controls cc ON cc.id = oc.parent_control_uuid
             WHERE oc.release_state = 'validated'
+              AND oc.merged_into_id IS NULL
               AND NOT EXISTS (
                   SELECT 1 FROM canonical_controls ac
                   WHERE ac.parent_control_uuid = oc.parent_control_uuid
                     AND ac.decomposition_method = 'pass0b'
-                    AND ac.release_state NOT IN ('deprecated', 'duplicate')
-                    AND ac.title LIKE '%' || LEFT(oc.action, 20) || '%'
+                    AND ac.release_state NOT IN ('deprecated')
               )
         """
         if limit > 0: