Add jvm-libp2p implementation for gossipsub-interop

[raulk]

Summary

Adds a JVM/Kotlin implementation of the gossipsub interop binary for Shadow network testing. This enables testing jvm-libp2p's gossipsub implementation alongside go-libp2p and rust-libp2p in the Shadow simulator.

Key additions:

• jvm-libp2p/ directory: Complete Kotlin implementation of the interop binary
• Key generation: Deterministic ED25519 key generation from node ID (little-endian encoded seed)
• Script parsing: Polymorphic JSON deserialization for all instruction types (start, connect, subscribe, publish, etc.)
• Partial messages: Full support for partial message testing (PeerDAS use case)
• Makefile integration: Build targets for JVM binaries and compositions

Usage

# Build the JVM binary
make gossipsub-interop-jvm

# Run with JVM nodes
uv run run.py --composition all-jvm --scenario partial-messages

Supported compositions

• all-jvm - All JVM nodes
• go-jvm - Go publisher, JVM subscriber
• jvm-go - JVM publisher, Go subscriber

Dependencies

This PR depends on: libp2p/jvm-libp2p#433

Test plan

• Shadow simulation passes with all-jvm composition
• Partial message exchange works between JVM nodes
• Cross-implementation testing (go-jvm, jvm-go)