Fix: React to external URL changes and cap tag-row height in library

Clicking the Reactbin home link (or any navigation to / that removes
?page=) now resets the displayed page by subscribing to queryParamMap
for post-init URL changes. Cards with many tags no longer push the
pagination bar down since the tag row is clamped to one line.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/app/library/library.component.spec.ts

@@ -8,12 +8,10 @@ import { ImageService } from '../services/image.service';
 import { routes } from '../app.routes';
 
 function makeActivatedRoute(queryParams: Record<string, string> = {}) {
+  const paramMap = { get: (key: string) => queryParams[key] ?? null };
   return {
-    snapshot: {
-      queryParamMap: {
-        get: (key: string) => queryParams[key] ?? null,
-      },
-    },
+    snapshot: { queryParamMap: paramMap },
+    queryParamMap: of(paramMap),
   };
 }