yarr needs rustc 1.97.1 but the main nixpkgs input (pinned by flake.lock)
has rustc 1.95.0. Bumping the main input breaks aioimaplib (email server
dep), so add a separate rust-nixpkgs input pinned to a newer rev.
yarr is excluded from the overlay (which uses the main nixpkgs) — build
it via 'nix build .#yarr' on the flake directly.
- Add flake structure with overlay and packages exports
- Add manim-mcp-server as first packaged MCP server
- Add README.org with usage instructions and package templates
- Add packages/default.nix as package aggregator
- Add overlays/default.nix for nixpkgs integration