fix(migrations): resolve PostgreSQL function type mismatch in get_ocr_queue_stats

migrations/20250708000001_simplify_ocr_queue_stats.sql

@@ -0,0 +1,29 @@
+-- Simplify get_ocr_queue_stats function to avoid CTE structure issues
+-- Use a simple SELECT with subqueries instead of CTEs and cross joins
+
+CREATE OR REPLACE FUNCTION get_ocr_queue_stats()
+RETURNS TABLE (
+    pending_count BIGINT,
+    processing_count BIGINT,
+    failed_count BIGINT,
+    completed_today BIGINT,
+    avg_wait_time_minutes DOUBLE PRECISION,
+    oldest_pending_minutes DOUBLE PRECISION
+) AS $$
+BEGIN
+    RETURN QUERY
+    SELECT 
+        COUNT(*) FILTER (WHERE status = 'pending') as pending_count,
+        COUNT(*) FILTER (WHERE status = 'processing') as processing_count,
+        COUNT(*) FILTER (WHERE status = 'failed' AND attempts >= max_attempts) as failed_count,
+        -- Get completed_today from documents table instead of ocr_queue
+        (SELECT COUNT(*)::BIGINT 
+         FROM documents 
+         WHERE ocr_status = 'completed'
+         AND updated_at >= CURRENT_DATE
+         AND updated_at < CURRENT_DATE + INTERVAL '1 day') as completed_today,
+        CAST(AVG(EXTRACT(EPOCH FROM (COALESCE(started_at, NOW()) - created_at))/60) FILTER (WHERE status IN ('processing', 'completed')) AS DOUBLE PRECISION) as avg_wait_time_minutes,
+        CAST(MAX(EXTRACT(EPOCH FROM (NOW() - created_at))/60) FILTER (WHERE status = 'pending') AS DOUBLE PRECISION) as oldest_pending_minutes
+    FROM ocr_queue;
+END;
+$$ LANGUAGE plpgsql;