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>

flake.lock

@@ -54,11 +54,11 @@
     },
     "nixpkgs-unstable": {
       "locked": {
-        "lastModified": 1751271578,
-        "narHash": "sha256-P/SQmKDu06x8yv7i0s8bvnnuJYkxVGBWLWHaU+tt4YY=",
+        "lastModified": 1751792365,
+        "narHash": "sha256-J1kI6oAj25IG4EdVlg2hQz8NZTBNYvIS0l4wpr9KcUo=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "3016b4b15d13f3089db8a41ef937b13a9e33a8df",
+        "rev": "1fd8bada0b6117e6c7eb54aad5813023eed37ccb",
         "type": "github"
       },
       "original": {
@@ -70,11 +70,11 @@
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1751479989,
-        "narHash": "sha256-M5KgdpVBVcW4HRVq9/OSRbrxlwsQ1ogEKqnvzsClDqU=",
+        "lastModified": 1751741127,
+        "narHash": "sha256-t75Shs76NgxjZSgvvZZ9qOmz5zuBE8buUaYD28BMTxg=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "34627c90f062da515ea358360f448da57769236e",
+        "rev": "29e290002bfff26af1db6f64d070698019460302",
         "type": "github"
       },
       "original": {