developer-guide: RPC dispatch moved from mod.rs handle_rpc_call to
dispatcher.rs dispatch() long ago — the registration instructions now point
at the real file; module tree updated (package/, federation/, mesh/ are
directories; mesh is tri-protocol); roadmap pointer loop/plan.md → docs/ROADMAP.md.
CONTRIBUTING: docs/development-setup.md never existed → developer-guide.md;
GitHub-specific fork URL generalized to the Gitea instance.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>