perf: optimize reconciliation candidate lookup

migrations/009_reconciliation_candidate_lookup_indexes.sql

@@ -0,0 +1,21 @@
+-- Structured lookup paths used by opportunity-detail reconciliation candidates.
+-- Existing opportunity, NIF and source/external indexes are intentionally reused.
+CREATE INDEX IF NOT EXISTS idx_reconciliation_customer_id
+ON reconciliation_items(customer_id)
+WHERE customer_id IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_reconciliation_customer_email_lower
+ON reconciliation_items(lower(customer_email))
+WHERE customer_email IS NOT NULL AND customer_email <> '';
+
+CREATE INDEX IF NOT EXISTS idx_reconciliation_customer_name_lower
+ON reconciliation_items(lower(customer_name))
+WHERE customer_name IS NOT NULL AND customer_name <> '';
+
+CREATE INDEX IF NOT EXISTS idx_commercial_documents_opportunity_number
+ON commercial_documents(opportunity_id, document_number)
+WHERE document_number IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_commercial_documents_opportunity_external
+ON commercial_documents(opportunity_id, external_id)
+WHERE external_id IS NOT NULL;