feat: add Home Manager refactoring plan and initial structure

- Add comprehensive Home Manager refactoring plan document
- Create initial Home Manager directory structure with user configs
- Add modular Emacs configuration for Home Manager integration
- Update system configurations for Home Manager compatibility
- Preserve existing functionality while preparing for migration

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

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

home-manager/modules/development/default.nix

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+# Shared development environment module
+# Contains common development tools and configurations
+
+{ config, lib, pkgs, ... }:
+
+{
+  # Shared development environment configuration
+  # Common development tools, language servers, formatters
+  # Development-specific environment variables
+}

home-manager/modules/development/languages.nix

@@ -0,0 +1,10 @@
+# Language-specific development configurations
+# Contains language servers, tools, and environment setup
+
+{ config, lib, pkgs, ... }:
+
+{
+  # Language-specific development tools
+  # LSP servers, formatters, linters for different languages
+  # Language-specific environment variables and configurations
+}