chore: update DS to v0.1.38, enforce 12px font size floor

Update @cameleer/design-system to v0.1.38 (12px minimum font size).
Replace all 10px and 11px font sizes with 12px across 25 CSS modules
and 5 TSX inline styles to match the new DS floor.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/auth/LoginPage.module.css

@@ -70,7 +70,7 @@
 
 .dividerText {
   color: var(--text-muted);
-  font-size: 11px;
+  font-size: 12px;
   text-transform: uppercase;
   letter-spacing: 0.5px;
   font-weight: 500;