add Claude Code integration

- Add CLAUDE.md with comprehensive repository documentation
- Configure claude-code package in editors feature
- Add MCP nixos integration for better Nix ecosystem support
- Include Claude settings with co-authored-by disabled
- Update unfree predicate for proprietary AI tools

CLAUDE.md

@@ -0,0 +1,67 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Repository Overview
+
+This is a NixOS and Home Manager configuration using flakes architecture, managing two hosts (`fuchsia` and `viridian`) with declarative system and user configurations.
+
+## Common Development Commands
+
+### System Management
+- `just build <hostname>` - Build system configuration without switching
+- `just switch <hostname>` - Build and switch to new system configuration (requires sudo)
+- `just deploy <hostname>` - Deploy configuration to remote host
+
+### Nix Operations
+- `nix build` - Build packages defined in flake
+- `nix fmt` - Format Nix files using alejandra formatter
+- `nix flake update` - Update all flake inputs
+- `nixos-rebuild build --flake .#<hostname>` - Build specific host configuration
+- `home-manager switch --flake .#sajenim@<hostname>` - Switch Home Manager configuration
+
+### Development Environment
+- `nix develop` - Enter development shell with `just` available
+- `nix-shell` - Legacy shell environment
+
+## Architecture
+
+### Flake Structure
+- **Main flake inputs**: nixpkgs (stable/unstable), home-manager, agenix/agenix-rekey, external configs
+- **Outputs**: NixOS configurations, Home Manager configurations, packages, overlays, modules
+- **Host configurations**: `fuchsia` (desktop) and `viridian` (server)
+
+### Directory Organization
+- `nixos/` - System-level configurations
+  - `common/global/` - Shared system configuration (nix settings, secrets, SSH)
+  - `common/users/` - User account definitions
+  - `common/optional/` - Optional system features (yubikey, persistence)
+  - `<hostname>/` - Host-specific configurations and services
+- `home-manager/` - User environment configurations
+  - `sajenim/features/` - Modular user features (cli, desktop, editors, games)
+  - `sajenim/global/` - Base user configuration
+- `modules/` - Custom NixOS and Home Manager modules
+- `pkgs/` - Custom package definitions
+- `overlays/` - Package modifications and patches
+
+### Key Features
+- **Ephemeral BTRFS**: Root filesystem is recreated on boot with opt-in persistence
+- **Secret Management**: agenix for encrypted secrets, rekeyed with YubiKey
+- **Modular Design**: Features organized as importable modules
+- **Custom Packages**: External configurations (nixvim, xmonad-config) as flake inputs
+
+### Host Profiles
+- **fuchsia**: Desktop workstation with X11, gaming, development tools
+- **viridian**: Server with multimedia stack (*arr services), web services, containers
+
+### Service Management
+- Services defined in `nixos/<hostname>/services/` and `nixos/<hostname>/multimedia/`
+- Docker containers managed through `virtualisation.oci-containers`
+- Traefik reverse proxy with automatic HTTPS
+- Borgbackup for persistent data
+
+### Configuration Patterns
+- All `.nix` files use `default.nix` for module entry points
+- Configurations use explicit imports for modular composition
+- Host-specific and shared configurations clearly separated
+- External dependencies managed through flake inputs

home-manager/sajenim/features/editors/claude-settings.json

@@ -0,0 +1,4 @@
+{
+  "outputStyle": "Explanatory",
+  "includeCoAuthoredBy": false
+}

home-manager/sajenim/features/editors/default.nix

@@ -14,6 +14,10 @@
       # Typesetting
       pandoc
       texliveFull
+
+      # AI-powered coding assistant and CLI tool
+      claude-code
+      unstable.mcp-nixos
     ]
     ++ [
       # Our personal neovim configuration.
@@ -27,13 +31,17 @@
       ])
     ]); # https://github.com/theCapypara/nix-jetbrains-plugins
 
-  # Allow unfree packages for jetbrains IDEs
+  # Allow unfree packages for proprietary software
   nixpkgs.config.allowUnfreePredicate = pkg:
     builtins.elem (lib.getName pkg) [
+      "claude-code"
       "idea-ultimate"
       "idea-ultimate-with-plugins" 
     ];
 
-  # Copy our vim configuration file for jetbrains IDEs
+  # Copy our configuration files to home directory
-  home.file.".ideavimrc".source = ./ideavimrc;
+  home.file = {
+    ".ideavimrc".source = ./ideavimrc;
+    ".claude/settings.json".source = ./claude-settings.json;
+  };
 }