Drop recent_account_transactions_mv

Add migration 048 to remove the unused indexer.recent_account_transactions_mv. The migration deletes any scheduled database_jobs that reference the view and drops the materialized view with CASCADE. This MV was created in migration 030, is not queried anywhere in the codebase, and its 4-hour refresh appeared as a top load query despite having no consumers.

Author: nelitow

packages/graphql/database/migrations/048_drop_unused_recent_account_transactions_mv.sql

@@ -0,0 +1,11 @@
+-- Migration 048: Drop unused recent_account_transactions_mv
+--
+-- This MV was created in migration 030 to optimize account transaction searches.
+-- It is not queried anywhere in the codebase — confirmed by grep of all source files.
+-- The 4-hour refresh job scans 7 days of transactions_accounts + transactions
+-- and shows up as the #3 load query in Performance Insights despite zero consumers.
+
+DELETE FROM indexer.database_jobs
+WHERE query LIKE '%recent_account_transactions_mv%';
+
+DROP MATERIALIZED VIEW IF EXISTS indexer.recent_account_transactions_mv CASCADE;