perf(web): cite #1931 as the initial-bytes baseline evidence

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/architecture/performance-journeys.md

@@ -1169,8 +1169,8 @@ mounts on every launch defer their Material views, the theme emits tokens only
 for imported components, and the app does not provide the animations module,
 which nothing used (Material 22 animates with CSS). Together these lowered the
 counter from 1,596,201 to 1,344,067 bytes (-252,134, 15.8%) on a local
-production build at the branch point; the baseline follows the measurement
-of the branch rebased onto `master`, 1,345,810. The snack-bar stays: root
+production build at the branch point (#1931); the baseline follows the
+measurement of the branch rebased onto `master`, 1,345,810. The snack-bar stays: root
 services inject it, and with it Material's button, the icon button chunk and
 the CDK overlay (about 190 KB) remain initial.