fix: honor nested Jackson annotations in tool schemas

[arnabnandy7]

Summary

Fixes #1884 by registering Victools’ JacksonModule when generating tool input schemas.

Nested Jackson annotations such as @JsonPropertyDescription are now reflected in the generated JSON Schema.

Changes

• Register JacksonModule in VictoolsSchemaGenerator
• Add regression coverage for descriptions on nested properties
• Reuse the Jackson-aware schema configuration pattern already present in the codebase

Testing

mvn -pl embabel-agent-api -Dtest=TypeBasedInputSchemaTest test

[arnabnandy7]

@simeshev thanks for the detailed review, good catch on the nested $defs references.

I’ve updated the configuration to:

• Disable subtype lookup so embedded parameter schemas don’t contain unresolved root references.
• Respect @JsonProperty(required = true) and @JsonPropertyOrder, matching the existing output-schema configuration.
• Add regression tests for polymorphic parameters, required properties, and property ordering.