paymentsdb: implement FetchInFlightPayments for sql backend

sqldb/sqlc/queries/payments.sql

@@ -40,15 +40,6 @@ FROM payments p
 LEFT JOIN payment_intents i ON i.payment_id = p.id
 WHERE p.payment_identifier = $1;
 
--- name: FetchPaymentsByIDs :many
-SELECT
-    sqlc.embed(p),
-    i.intent_type AS "intent_type",
-    i.intent_payload AS "intent_payload"
-FROM payments p
-LEFT JOIN payment_intents i ON i.payment_id = p.id
-WHERE p.id IN (sqlc.slice('payment_ids')/*SLICE:payment_ids*/);
-
 -- name: CountPayments :one
 SELECT COUNT(*) FROM payments;
 
@@ -86,8 +77,26 @@ FROM payment_htlc_attempts ha
 LEFT JOIN payment_htlc_attempt_resolutions hr ON hr.attempt_index = ha.attempt_index
 WHERE ha.payment_id IN (sqlc.slice('payment_ids')/*SLICE:payment_ids*/);
 
+-- name: FetchPaymentsByIDs :many
+-- Batch fetch payment and intent data for a set of payment IDs.
+-- Used to avoid fetching redundant payment data when processing multiple
+-- attempts for the same payment.
+SELECT
+    p.id,
+    p.amount_msat,
+    p.created_at,
+    p.payment_identifier,
+    p.fail_reason,
+    pi.intent_type,
+    pi.intent_payload
+FROM payments p
+LEFT JOIN payment_intents pi ON pi.payment_id = p.id
+WHERE p.id IN (sqlc.slice('payment_ids')/*SLICE:payment_ids*/)
+ORDER BY p.id ASC;
+
 -- name: FetchAllInflightAttempts :many
--- Fetch all inflight attempts across all payments
+-- Fetch all inflight attempts with their payment data using pagination.
+-- Returns attempt data joined with payment and intent data to avoid separate queries.
 SELECT
     ha.id,
     ha.attempt_index,
@@ -104,7 +113,9 @@ WHERE NOT EXISTS (
     SELECT 1 FROM payment_htlc_attempt_resolutions hr
     WHERE hr.attempt_index = ha.attempt_index
 )
-ORDER BY ha.attempt_index ASC;
+AND ha.attempt_index > $1
+ORDER BY ha.attempt_index ASC
+LIMIT $2;
 
 -- name: FetchHopsForAttempts :many
 SELECT