Change JSON Schema lib

[yoshiori]

This PR removes the Scala dependency from the project by replacing mbknor-jackson-jsonschema_2.12 with victools/jsonschema-generator, a modern, actively maintained JSON Schema
generator.

Background

Old Library (mbknor-jackson-jsonschema):

• Last meaningful activity: 2020 (4+ years ago)
• Status: No longer maintained by original author, migrated to HubSpot fork
• Scala dependency: Required Scala 2.12 runtime
• JSON Schema version: Draft 4 (2013 specification)

New Library (victools/jsonschema-generator):

• Latest release: v4.38.0 (March 24, 2025)
• Activity: Actively maintained with regular releases and community engagement
• Language: Pure Java (no Scala dependency)
• JSON Schema version: Draft 7 compliance

OpenAI API Compatibility

The new implementation uses JSON Schema Draft 7, which is officially supported by OpenAI:

• Evidence: OpenAI's official Node.js SDK (openai-node) explicitly uses Draft 7 in their
  https://github.com/openai/openai-node/blob/1a3850112451e81840840c960bf6925753d4fac3/src/lib/jsonschema.ts#L52
• Recommended schema: http://json-schema.org/draft-07/schema#

[Copilot]

Pull Request Overview

This PR migrates from the deprecated Scala-based JSON schema generator to a modern Java library, removing the Scala dependency and updating to JSON Schema Draft 7 for better OpenAI compatibility.

Key changes:

• Replace mbknor-jackson-jsonschema with victools/jsonschema-generator for active maintenance and Draft 7 support
• Remove Scala dependency by switching to pure Java implementation
• Update Gradle wrapper version to 8.11.1

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
ChatFunctionParametersSerializer.java	Replace deprecated JSON schema generator with victools implementation
service/build.gradle	Update dependencies to use new JSON schema libraries
gradle/wrapper/gradle-wrapper.properties	Upgrade Gradle wrapper version
gradle/libs.versions.toml	Add new library versions and remove old Scala dependency

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[Konboi]

CI failed due to LAUNCHABLE_TOKEN issue.
Let's check it after merge to the main