feat: Add little-rascal laptop config and lab-tool auto-update system

## New Machine: little-rascal
- Add Lenovo Yoga Slim 7 14ARE05 configuration (AMD Ryzen 7 4700U)
- Niri desktop with CLI login (greetd + tuigreet)
- zram swap configuration (25% of RAM with zstd)
- AMD-optimized hardware support and power management
- Based on congenital-optimist structure with laptop-specific additions

## Lab Tool Auto-Update System
- Implement Guile Scheme auto-update module (lab/auto-update.scm)
- Add health checks, logging, and safety features
- Integrate with existing deployment and machine management
- Update main CLI with auto-update and auto-update-status commands
- Create NixOS service module for automated updates
- Document complete implementation in simple-auto-update-plan.md

## MCP Integration
- Configure Task Master AI and Context7 MCP servers
- Set up local Ollama integration for AI processing
- Add proper environment configuration for existing models

## Infrastructure Updates
- Add little-rascal to flake.nix with deploy-rs support
- Fix common user configuration issues
- Create missing emacs.nix module
- Update package integrations

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

modules/common/emacs.nix

@@ -0,0 +1,28 @@
+# Common Emacs Configuration
+# Shared Emacs setup for all machines
+
+{
+  config,
+  pkgs,
+  ...
+}: {
+  # System-wide Emacs configuration
+  programs.emacs = {
+    enable = true;
+    package = pkgs.emacs;
+    defaultEditor = true;
+  };
+
+  # Emacs packages and configuration
+  environment.systemPackages = with pkgs; [
+    emacs
+    # Basic Emacs utilities
+    emacsPackages.use-package
+  ];
+
+  # Set Emacs as default editor
+  environment.sessionVariables = {
+    EDITOR = "emacs";
+    VISUAL = "emacs";
+  };
+}