[Feature]: Migrate the pages from Radzen to Blazor Blueprint  #62

What type of issue is this?

• Bug report
• Feature request

Prerequisites

• I have written a descriptive issue title
• I have verified that I am running the latest version of the reqifviewer
• I have searched open and closed issues to ensure it has not already been reported

Description

The app shell moved to Blazor Blueprint in #56; the pages still use Radzen components (14 data grids, 59 headings, 39 cards) and the Bootstrap grid, with a temporary bridge section in app.css.

Acceptance criteria

• Shared components first (AttributeValuesComponent, SpecObjectComponent), then the list pages (14 Radzen data grids to the Blueprint Data Grid), then the specification tree.
• Radzen, Bootstrap, open-iconic and the "bridge" CSS in app.css are removed; Blueprint is imported in the root _Imports.razor.
• Light and dark mode work on every page.
• Note: phase 1 replaces several of these pages; migrate only what phase 1 keeps.

Steps to Reproduce

Load requirements-and-objects.reqifz or ProR_Traceability-Template-v1.0.reqif (reqifviewer.Tests/TestData) and look at the pages mentioned above.

System Configuration

• reqifviewer version: 6.1.0 (development, with [Refactor] Blazor Blueprint app shell and Blazor Web App hosting #56)
• Environment (Operating system, version and so on): Windows 11, Chrome
• .NET Framework version: .NET 10
• Additional information: Plan item F-06 of the viewer improvement plan. Size: L.