WebUI Architecture Cleanup (#19541)

* webui: architecture foundation (non-MCP core refactors)

* chore: update webui build output

tools/server/webui/src/lib/constants/css-classes.ts

@@ -0,0 +1,10 @@
+export const BOX_BORDER =
+	'border border-border/30 focus-within:border-border  dark:border-border/20 dark:focus-within:border-border';
+
+export const INPUT_CLASSES = `
+    bg-muted/60 dark:bg-muted/75
+    ${BOX_BORDER}
+    shadow-sm
+    outline-none
+    text-foreground
+`;