Use a struct for ClientContext (fix #169)

[sebsto]

Do not use a String for Lambdacontext.ClientContext, use a struct instead
fix for #169

Note: this PR introduces an API change that will break function using LambdaContext, we should integrate this change during the beta otherwise it will require a major version bump.

Motivation:

Let the compiler detect type errors for us

Modifications:

• Create a struct for ClientContext and it's embedded ClientApplication
• add three unit test to validate the struct

Result:

No more String?

[Copilot]

Pull Request Overview

This PR replaces the string-based ClientContext implementation with strongly-typed structs to provide better type safety and compiler error detection for AWS Lambda runtime client context data.

• Replaces String? type with structured ClientContext and ClientApplication types
• Adds proper JSON encoding/decoding with snake_case field mapping for AWS compatibility
• Includes comprehensive unit tests covering various ClientContext scenarios

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
Sources/AWSLambdaRuntime/LambdaContext.swift	Introduces ClientContext and ClientApplication structs with proper Codable implementation and updates LambdaContext to use the new types
Tests/AWSLambdaRuntimeTests/LambdaContextTests.swift	Adds comprehensive test suite covering JSON encoding/decoding scenarios for the new ClientContext types

[sebsto]

Hello @ktoso
This is the oldest open issue on this project
#169

You opened it 5 years ago :-)
Can you review the change, and provide feedback or approve it ?

Thanks

[ktoso]

Looks good to me, thank you for addressing this, it's been a while huh!