webui: Improve Chat Messages initial scroll + auto-scroll logic + add lazy loading with transitions to content blocks (#20999)

* refactor: Always use agentic content renderer for Assistant Message

* feat: Improve initial scroll + auto-scroll logic + implement fade in action for content blocks

* chore: update webui build output

tools/server/webui/src/lib/constants/auto-scroll.ts

@@ -1,3 +1,2 @@
 export const AUTO_SCROLL_INTERVAL = 100;
-export const INITIAL_SCROLL_DELAY = 50;
 export const AUTO_SCROLL_AT_BOTTOM_THRESHOLD = 10;