Add Apache Thrift IDL support

[clemensv]

Feature request

Add first-class conversion support for Apache Thrift IDL (.thrift).

Motivation

Thrift remains common in service contracts and internal data schemas; supporting it would improve interoperability with existing backends and schema repositories.

Suggested scope

• Import: hrift2a (Thrift -> Avrotize Schema)
• Export: ^G2thrift (Avrotize Schema -> Thrift)
• Handle structs, enums, unions, typedefs, required/optional fields, containers (list, set, map), and namespace mapping
• Include roundtrip fixtures and CLI tests

Acceptance criteria

• New CLI commands documented in README and commands.json
• Conversion tests for primitives, nested types, enums/unions, and references
• Stable output for golden fixtures

Additional requirement: JSON Structure conversions

Please also include JSON Structure conversion support in scope:

• hrift2s (Thrift -> JSON Structure)
• s2thrift (JSON Structure -> Thrift)
• Keep mappings consistent with hrift2a/�2thrift and document any lossy areas.

[clemensv]

Additional requirement for this issue:
Please include JSON Structure conversion support in scope as well (import to JSON Structure and export from JSON Structure), with tests and documented mapping limitations where needed.