Publish Android SDK to Raft Artifacts

[bytemain]

Problem

The Hands Android SDK is published only to GitHub Packages, which requires a GitHub token even for public consumption.

Changes

• add https://maven.artifacts.botiverse.dev as a publication target for build.hands:hands-android-sdk
• require the repository-scoped publication credential in the release workflow instead of silently skipping the target
• extend the publication gate to prove the Raft Artifacts task is in the remote publication graph
• document anonymous public consumption from Raft Artifacts

Follow-up

Run one prerelease publication and resolve it from a clean Gradle cache before using this target for the next SDK release.

Testing

• bash -n scripts/test_android_publication_gate.sh
• workflow YAML parse
• git diff --check
• hosted Android publication gate and prerelease publish will run on this exact branch