Upgrade MudBlazor to v9

[neozhu]

Upgrade MudBlazor to v9

Summary

This PR upgrades MudBlazor from v6.x/v7.x to v9, along with all necessary breaking change migrations across the Blazor Server UI project. The upgrade also targets .NET 10.

Motivation

MudBlazor v9 introduces significant performance improvements, new components, a modernized API surface, and improved accessibility. This upgrade ensures the project stays current with the latest framework capabilities and security patches.

Breaking Changes Addressed

Component API Changes

• IMudDialogInstance — Replaced legacy MudDialogInstance with the new IMudDialogInstance interface for dialog cascading parameters
• MudLoadingButton — Adopted the new MudLoadingButton component (replacing manual loading state patterns on MudButton)
• DialogResult.Ok() — Updated dialog result API to match v9 signatures

Theme & Styling

• UserPreference — Implemented custom HSL-based color brightness adjustment (AdjustBrightness) using System.Drawing.ColorTranslator for PrimaryDarken / PrimaryLighten computed properties
• Tailwind-aligned color palette — Updated primary colors to Tailwind 600 scale (light mode) and 500 scale (dark mode) for better contrast and accessibility
• Typography system — Added computed font size, line height, and letter spacing properties for consistent responsive typography (H5, H6, Body1, Body2, Button, Caption, Overline, Subtitle1, Subtitle2)

Dialog System

• Migrated all dialog components to use [CascadingParameter] IMudDialogInstance MudDialog instead of the previous MudDialogInstance
• Updated MudDialog.Close() and MudDialog.Cancel() calls to the v9 API

Validation

• Continued use of IValidationService with Validator.ValidateValue() pattern for MudForm validation, verified compatible with v9

Package Updates

Package	Previous	Updated
MudBlazor	v6.x / v7.x	v9.x
Target Framework	.NET 9	.NET 10

Changes Overview

• ✅ Updated MudBlazor NuGet package to v9
• ✅ Migrated dialog components to IMudDialogInstance
• ✅ Adopted MudLoadingButton for async submit buttons
• ✅ Refactored theme/user preference system with computed color properties
• ✅ Updated _Imports.razor for v9 namespace changes
• ✅ Fixed all compilation errors from breaking API changes
• ✅ Verified all unit tests pass (33/33 ✅)

Testing

• Application.UnitTests: 28 passed ✅
• Domain.UnitTests: 5 passed ✅
• Build: Successful with no errors

Screenshots

N/A — UI behavior unchanged; theme colors may appear slightly different due to Tailwind palette alignment.

Checklist

• MudBlazor v9 package updated
• All breaking changes resolved
• Theme system updated with new color computation
• Dialog components migrated to new API
• Unit tests passing
• Build succeeds with no errors
• No regressions in existing functionality