Initial commit: MCP server packages for Nix

- 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

.gitignore

@@ -0,0 +1,27 @@
+# Nix
+result
+result-*
+
+# direnv
+.direnv/
+
+# Editor files
+*~
+\#*\#
+.#*
+*.swp
+*.swo
+
+# macOS
+.DS_Store
+
+# IDE
+.idea/
+.vscode/
+*.code-workspace
+
+# Agent transcripts
+.agent-shell/
+
+# Local environment overrides
+.envrc.local