[pournasserian]

Closes #2631

What

A Low finding from the independent review of #2568 (F-DSK, #2422). A page that didn't parse, such as abc or 99999999999, answered an empty 500 on the desk and on /security.

• The desk and the security view read page as text and parse it with int.TryParse. A value that doesn't parse shows the first page, as 0 and negative values already did.

Why

• Text, not int?. Blazor throws while binding a query value that doesn't parse, before the page can fall back. Reading text keeps the fallback in the page.

Tests

• bUnit: page=abc, page=99999999999 and an empty page show the first page on both views.
• Host: the same addresses answer 200 on both views.

dotnet build -warnaserror, the unit and bUnit suite and the desk host tests pass locally. No new package and no new project reference.

Checklist

• Linked to an issue a maintainer has confirmed
• Targets v2
• Tests or docs updated where behaviour changed
• No tool-generated co-author trailers or footers