Add Smithy operation model translation to codegen

[Fred1155]

Motivation and Context

This PR adds the operation layer for smithy codegen migration. It's the Smithy-side counterpart to AddOperations (plus the empty input/output handling that C2J splits into AddEmptyInputShape/AddEmptyOutputShape). The goal is given the same API, produce the same OperationModels the C2J path produces. It's not wired into the generator yet and that happens in a later PR that adds the builder.

Modifications

Add AddSmithyOperations, which walks the operations reachable from a Smithy service and fills in one OperationModel each: name, protocol, deprecation, documentation, input/output types (including Unit synthesis), payload flags, exceptions, endpoint discovery, endpoint host prefix, checksums, request compression, context params, unsigned payload, and auth.
Add a ProtocolUtils.resolveProtocol(ServiceIndex, ServiceShape) overload that maps a service's applied Smithy protocol traits to the SDK protocol string, reusing the existing priority list so multi-protocol services (e.g. awsQuery + awsJson1_0) resolve the same way the C2J path resolves them.

Pagination (isPaginated) is intentionally left unset here; it depends on paginator data that a later PR adds.

Testing

AddSmithyOperationsTest and ProtocolUtilsTest covers the new overload including the multi-protocol case and the unsupported-protocol error.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Checklist

• I have read the CONTRIBUTING document
• Local run of mvn install succeeds
• My code follows the code style of this project
• My change requires a change to the Javadoc documentation
• I have updated the Javadoc documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed
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• My change is to implement 1.11 parity feature and I have updated LaunchChangelog

License

• I confirm that this pull request can be released under the Apache 2 license