Upgrade .NET Framework from 4.5.1 to 4.8.1 and update NuGet packages

[devin-ai-integration]

Summary

This PR upgrades the ASP.NET MVC 5 application from .NET Framework 4.5.1 to 4.8.1 as Phase 1 of the planned migration to .NET 8. All NuGet packages have been updated to their latest Framework-compatible versions.

Framework Changes:

• Updated TargetFrameworkVersion from v4.5.1 to v4.8.1 in all 5 .csproj files
• Updated Web.config compilation and httpRuntime targetFramework to 4.8

Key Package Upgrades:

Package	Old Version	New Version
EntityFramework	6.1.3	6.5.1
Autofac	3.5.0	4.9.4
AutoMapper	4.2.1	10.1.1
Newtonsoft.Json	6.0.4	13.0.3
Microsoft.AspNet.Mvc	5.2.3	5.2.9
Microsoft.Owin.*	3.0.0	4.2.2
NUnit	2.6.3	3.14.0
Moq	4.2.x	4.20.70

All assembly references in .csproj files and binding redirects in Web.config have been updated to match the new package versions.

Review & Testing Checklist for Human

• Build verification on Windows - The build could not be verified locally (Linux/Mono doesn't support .NET 4.8.1). Verify the solution builds successfully on Windows with Visual Studio or MSBuild.
• AutoMapper compatibility - AutoMapper jumped from 4.x to 10.x which has significant API changes. Verify that AutoMapper configurations and mappings still work correctly (check ServiceLayer DTOs and any Mapper.Map calls).
• Autofac DI configuration - Autofac 4.x has breaking changes from 3.x. Verify SampleWebApp/Infrastructure/AutofacDi.cs still configures the container correctly.
• NUnit test compatibility - NUnit 3.x has different attribute names and assertion syntax from 2.x. Run the test suite and verify all tests pass or update test syntax as needed.
• Runtime smoke test - Deploy to a test environment and verify the application starts and basic CRUD operations work (Posts, Tags, Blogs).

Recommended Test Plan:

1. Open solution in Visual Studio on Windows and verify it builds without errors
2. Run all unit tests in the Tests project
3. Start the application locally and navigate through the main pages
4. Test creating/editing/deleting a Post to verify EF and AutoMapper work correctly

Notes

• The AutoMapper.Net4.dll reference and AutoMapper.targets import were removed from BizLayer.csproj as they are no longer part of AutoMapper 10.x
• jQuery was upgraded from 1.10.2 to 3.7.1 and Bootstrap from 3.3.2 to 3.4.1 - verify frontend functionality

Link to Devin run: https://app.devin.ai/sessions/f3cd02d0f03f4167804b2c6db45849a9
Requested by: @mbatchelor81

[devin-ai-integration]

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