Auto-derive SDK version from assembly metadata

[jmarbutt]

Problem

The SDK version is hard-coded in InngestClient:

private readonly string _sdkVersion = "1.3.4";

This can drift from the actual package version and report incorrect SDK info during sync/inspection requests.

Location: Inngest/InngestClient.cs:33

Suggested Solution

Derive the version from assembly metadata at runtime:

private static readonly string _sdkVersion = 
    typeof(InngestClient).Assembly
        .GetCustomAttribute<AssemblyInformationalVersionAttribute>()
        ?.InformationalVersion?.Split('+')[0] 
    ?? "0.0.0";

Or use AssemblyFileVersionAttribute if InformationalVersion includes git hash.

Benefits

• Version always matches the NuGet package
• No manual updates needed when bumping versions
• More reliable debugging/support

Priority

Low - minor inconvenience, doesn't affect functionality.