Fix Dashboard.Web to use only .NET Standard 2.0 APIs for H5 transpilation

[MelbourneDeveloper]

Problem Statement

Dashboard.Web targets netstandard2.1 but H5 (C# to JavaScript transpiler) only supports .NET Standard 2.0 APIs. Code using netstandard2.1-specific APIs fails to transpile to JavaScript.

Current State

• Dashboard.Web.csproj: <TargetFramework>netstandard2.1</TargetFramework>
• H5 version: 24.11.53878 (Nov 2024) - Latest is 26.2.64289
• H5 transpilation: DISABLED (wwwroot/index.html:102) due to React hooks incompatibility
• Current workaround: Pure JavaScript with React

Desired Outcome

1. Upgrade H5 package to 26.2.64289 or latest stable
2. Downgrade to netstandard2.0 OR constrain code to use only 2.0 APIs
3. Re-enable H5 transpilation
4. Verify React hooks compatibility

Success Criteria

• H5 transpilation enabled and generates valid JavaScript
• No runtime errors from transpiled code
• React components work correctly

Overarching Goal

Enable offline-first Dashboard with browser SQLite and shared type-safe code between microservices and frontend.

[MelbourneDeveloper]

Closing - this contradicts #20. Replacing with correct issues that present two mutually exclusive paths.