Generate MCP classes with OpenAPI Generator (#294)

- Add OpenAPI Generator to build system to automatically generate MCP
protocol data classes from the official schema.
- Configure code quality tools to exclude generated files
- Add deserialization test

## Motivation and Context

Writing classes by hand is error-prone, when json schema exists. See
#185,
Also, autogenerating model classes ensures the SDK is in sync with the
protocol and can quickly catch up with its changes (see #218)

## How Has This Been Tested?
Regression tests

## Breaking Changes
No

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->

gradle/libs.versions.toml

@@ -48,6 +48,7 @@ ktor-server-core = { group = "io.ktor", name = "ktor-server-core", version.ref =
 
 # Testing
 awaitility = { group = "org.awaitility", name = "awaitility-kotlin", version.ref = "awaitility" }
+kotest-assertions-core = { group = "io.kotest", name = "kotest-assertions-core", version.ref = "kotest" }
 kotest-assertions-json = { group = "io.kotest", name = "kotest-assertions-json", version.ref = "kotest" }
 kotlinx-coroutines-test = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-test", version.ref = "coroutines" }
 ktor-client-mock = { group = "io.ktor", name = "ktor-client-mock", version.ref = "ktor" }