sqldb+graph/db: implement FilterChannelRange

This lets us run `TestFilterChannelRange` against the SQL backends.

sqldb/sqlc/queries/graph.sql

@@ -317,6 +317,13 @@ FROM channels c
 WHERE c.version = $1
   AND (c.node_id_1 = $2 OR c.node_id_2 = $2);
 
+-- name: GetPublicV1ChannelsBySCID :many
+SELECT *
+FROM channels
+WHERE node_1_signature IS NOT NULL
+  AND scid >= @start_scid
+  AND scid < @end_scid;
+
 -- name: ListChannelsWithPoliciesPaginated :many
 SELECT
     sqlc.embed(c),
@@ -420,6 +427,13 @@ ON CONFLICT (channel_id, node_id, version)
 WHERE EXCLUDED.last_update > channel_policies.last_update
 RETURNING id;
 
+-- name: GetChannelPolicyByChannelAndNode :one
+SELECT *
+FROM channel_policies
+WHERE channel_id = $1
+  AND node_id = $2
+  AND version = $3;
+
 /* ─────────────────────────────────────────────
    channel_policy_extra_types table queries
    ─────────────────────────────────────────────