User peer naming is inconsistent with the other Honcho plugins

[rrei]

The OpenCode plugin stores the user as a user-<peerName> peer, while the Claude Code and Hermes plugins use the bare <peerName>. When these plugins share a workspace, the user's memory is silently split: OpenCode writes to its own peer and never sees or contributes to what the other tools learn.

The fix is to drop the prefix so OpenCode uses the bare peerName, matching the sibling plugins.

[adavyas]

thanks for raising this issue! merged with PR #24