Add http-1x codegen support for server SDK generation

[drganjoo]

This commit introduces comprehensive http-1x support to the server code generator,
enabling generation of server SDKs that work with either [email protected] or [email protected]
based on the http-1x codegen flag.

Key Changes

New Infrastructure

• HttpDependencies.kt: New data class that ensures cohesive HTTP dependency
  selection, preventing accidental mixing of HTTP 0.x and 1.x versions. Provides
  helper methods for accessing HTTP types (Request, Response, HeaderMap, etc.)

• MultiVersionTestFailure.kt: Test infrastructure for tracking failures by
  HTTP version, enabling tests to run against both http@0 and http@1

ServerCodegenConfig Updates

• Add http1x boolean field to control HTTP version selection (config key: http-1x)
• Defaults to false ([email protected])

ServerCodegenContext Updates

• Add isHttp1() method to check if http-1x is enabled
• Add httpDependencies() method to provide version-appropriate HTTP dependencies
  throughout code generation

ServerRequiredCustomizations

• Update to create and manage HttpDependencies based on http-1x setting
• For http@0: use aws-smithy-legacy-http-server
• For http@1: use aws-smithy-http-server

Protocol & Test Generator Updates

• ServerProtocolTestGenerator: Support running protocol tests against both
  HTTP versions, with configurable test runtime mode (AS_CONFIGURED, BOTH, etc.)
• ServerHttpBoundProtocolGenerator: Use HttpDependencies for all HTTP type
  references instead of hardcoded dependencies

Generator Updates

Updated generators to use HttpDependencies for type resolution:

• ServerRootGenerator: Use httpDeps for dependency selection
• ServerServiceGenerator: Pass HttpDependencies to child generators
• ServerHttpSensitivityGenerator: Use httpDeps for HTTP types
• ServerOperationGenerator, ServerBuilderGenerator: Use contextual HTTP deps

Test Infrastructure

• ServerCodegenIntegrationTest: Add multi-version test support with
  ability to run tests against both HTTP versions
• Http1xDependencyTest: New test validating correct dependency selection
  based on http-1x flag
• Update existing tests to work with multi-version infrastructure

Core Changes

• HttpBindingGenerator: Accept HttpDependencies parameter for version-appropriate
  type generation
• EventStream generators: Use contextual HTTP dependencies
• SmithyTypesPubUseExtra: Conditional imports based on HTTP version

Testing

All protocol tests can now run against both HTTP versions to ensure compatibility.
Tests track failures by HTTP version for easier debugging.

Relates to #3362

[rcoh]

I would recommend that we actually make RuntimeConfig "do the right thing". Or make it so that you MUST pass an http version setting when getting the dependencies that depend on it.

You could incorporate the http1x setting into RuntimeConfig potentially, then make things like smithyHttp http version aware?

I'm worried that the way the code works right now will be somewhat confusing for folks to deal with and create these really confusing compilation errors.

[rcoh]

did you want to leave these printlns?

[rcoh]

I think we should probably have ServerCargoDependency.smithyHttpServerAuto that automatically gives you the right one. I think the http version would actually fit pretty naturally into RuntimeConfig as an optional parameter.

[rcoh]

But if you just want to ship things like it is, I get that. I'm just kinda worried about the long term fallout of having it be non-centralized especially as we eventually try to get rid of the old codegen settings.