Migrate from home-manager neovim to NixVim

Major configuration migration following 2025 best practices:

- Add nixvim flake input with proper nixpkgs following
- Import nixvim.homeManagerModules.nixvim in home configuration
- Convert nvim.nix from programs.neovim to programs.nixvim
- Migrate all settings to declarative NixVim syntax:
  * vim.opt.* → opts.*
  * vim.g.mapleader → globals.mapleader
  * Raw Lua keymaps → structured keymaps array
  * Plugin configs → declarative plugin options
- Preserve all functionality:
  * Gruvbox hard contrast colorscheme
  * nvim-tree with dotfile/gitignore filters
  * Treesitter with all grammars
  * Lualine with relative paths and gruvbox theme
  * Fugitive git integration
  * System clipboard keybindings
  * All leader key mappings

Benefits: Type safety, better documentation, cleaner code structure

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

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

flake.lock

@@ -19,6 +19,27 @@
         "type": "github"
       }
     },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": [
+          "nixvim",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1753121425,
+        "narHash": "sha256-TVcTNvOeWWk1DXljFxVRp+E0tzG1LhrVjOGGoMHuXio=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "644e0fc48951a860279da645ba77fe4a6e814c5e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "flake-utils": {
       "inputs": {
         "systems": "systems"
@@ -37,6 +58,24 @@
         "type": "github"
       }
     },
+    "flake-utils_2": {
+      "inputs": {
+        "systems": "systems_2"
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "home-manager": {
       "inputs": {
         "nixpkgs": [
@@ -57,6 +96,34 @@
         "type": "github"
       }
     },
+    "ixx": {
+      "inputs": {
+        "flake-utils": [
+          "nixvim",
+          "nuschtosSearch",
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixvim",
+          "nuschtosSearch",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1748294338,
+        "narHash": "sha256-FVO01jdmUNArzBS7NmaktLdGA5qA3lUMJ4B7a05Iynw=",
+        "owner": "NuschtOS",
+        "repo": "ixx",
+        "rev": "cc5f390f7caf265461d4aab37e98d2292ebbdb85",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NuschtOS",
+        "ref": "v0.0.8",
+        "repo": "ixx",
+        "type": "github"
+      }
+    },
     "nix-darwin": {
       "inputs": {
         "nixpkgs": [
@@ -110,12 +177,59 @@
         "type": "github"
       }
     },
+    "nixvim": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "nuschtosSearch": "nuschtosSearch",
+        "systems": "systems_3"
+      },
+      "locked": {
+        "lastModified": 1753533009,
+        "narHash": "sha256-4KlfDVsYL9c3ogEehJcQOBZ+pUBH7Lwvlu2J6FCtSJc=",
+        "owner": "nix-community",
+        "repo": "nixvim",
+        "rev": "29edaafdb088cee3d8c616a4a5bb48b5eecc647c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixvim",
+        "type": "github"
+      }
+    },
+    "nuschtosSearch": {
+      "inputs": {
+        "flake-utils": "flake-utils_2",
+        "ixx": "ixx",
+        "nixpkgs": [
+          "nixvim",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1753450833,
+        "narHash": "sha256-Pmpke0JtLRzgdlwDC5a+aiLVZ11JPUO5Bcqkj0nHE/k=",
+        "owner": "NuschtOS",
+        "repo": "search",
+        "rev": "40987cc1a24feba378438d691f87c52819f7bd75",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NuschtOS",
+        "repo": "search",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "claude-code": "claude-code",
         "home-manager": "home-manager",
         "nix-darwin": "nix-darwin",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": "nixpkgs_2",
+        "nixvim": "nixvim"
       }
     },
     "systems": {
@@ -132,6 +246,36 @@
         "repo": "default",
         "type": "github"
       }
+    },
+    "systems_2": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "systems_3": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",