added downloaded_at timestamp to icon table

pipeline/01_cc_index/schema.sql

@@ -30,7 +30,8 @@ CREATE TABLE IF NOT EXISTS icons (
     file_size INT,
     s3_key TEXT,
     scan_state TEXT DEFAULT 'unscanned',
-    error TEXT
+    error TEXT,
+    downloaded_at TIMESTAMPTZ
 );
 
 -- Partial index: only unscanned icons (shrinks as work completes)

pipeline/03_icon_download/db.go

@@ -69,7 +69,8 @@ func updateIcon(ctx context.Context, pool *pgxpool.Pool, iconID int64, result Do
 			content_type = $2,
 			width = $3,
 			height = $4,
-			file_size = $5
+			file_size = $5,
+			downloaded_at = now()
 		WHERE id = $6`,
 		result.S3Key, result.ContentType,
 		nilIntIf(result.Width, 0), nilIntIf(result.Height, 0),