Establish project foundation: domain model, MVI spec, environment reference

Capture the design work for the NixOS migration before any implementation:

- .claude/CONTEXT.md: domain glossary (Host, Module, Skeleton, Auto-loader,
  Enable convention, unstable/stable overlay)
- .claude/adr/0001-sops-nix-for-secrets.md: secrets tooling decision
- .claude/spec/laptop-mvi.md: frozen minimum-viable-install spec for neogaia

- reference/: read-only snapshot of the current CachyOS configs (secrets and
  state excluded), plus ENVIRONMENT.md profiling the live environment to guide
  replication

reference/home/.config/nvim/lua/keys.lua

@@ -0,0 +1,8 @@
+local map = vim.keymap.set
+
+map("n", "<C-h>", "<C-w>h", { desc = "Move focus left" })
+map("n", "<C-j>", "<C-w>j", { desc = "Move focus down" })
+map("n", "<C-k>", "<C-w>k", { desc = "Move focus up" })
+map("n", "<C-l>", "<C-w>l", { desc = "Move focus right" })
+
+map("n", "<Esc>", "<cmd>nohlsearch<CR>", { desc = "Clear search highlight" })

reference/home/.config/nvim/lua/plugin.lua

@@ -0,0 +1,23 @@
+local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
+if not vim.uv.fs_stat(lazypath) then
+  local lazyrepo = "https://github.com/folke/lazy.nvim.git"
+  local out = vim.fn.system({ "git", "clone", "--filter=blob:none", "--branch=stable", lazyrepo, lazypath })
+  if vim.v.shell_error ~= 0 then
+    vim.api.nvim_echo({
+      { "Failed to clone lazy.nvim:\n", "ErrorMsg" },
+      { out, "WarningMsg" },
+      { "\nPress any key to exit..." },
+    }, true, {})
+    vim.fn.getchar()
+    os.exit(1)
+  end
+end
+vim.opt.rtp:prepend(lazypath)
+
+require("lazy").setup({
+  spec = {
+    { import = "plugins" },
+  },
+  install = { colorscheme = { "nord" } },
+  checker = { enabled = false },
+})

reference/home/.config/nvim/lua/plugins/git.lua

@@ -0,0 +1,36 @@
+return {
+  {
+    "NeogitOrg/neogit",
+    dependencies = {
+      "nvim-lua/plenary.nvim",
+      "sindrets/diffview.nvim",
+    },
+    keys = {
+      {
+        "<leader>g",
+        function()
+          require("gitsigns").toggle_current_line_blame(true)
+          require("neogit").open()
+        end,
+        desc = "Open git (Neogit)",
+      },
+    },
+    config = function()
+      require("neogit").setup()
+      vim.api.nvim_create_autocmd("BufUnload", {
+        callback = function(args)
+          if vim.bo[args.buf].filetype == "NeogitStatus" then
+            require("gitsigns").toggle_current_line_blame(false)
+          end
+        end,
+      })
+    end,
+  },
+  {
+    "lewis6991/gitsigns.nvim",
+    event = "BufWinEnter",
+    opts = {
+      current_line_blame = false,
+    },
+  },
+}

reference/home/.config/nvim/lua/plugins/navigation.lua

@@ -0,0 +1,27 @@
+return {
+  {
+    "stevearc/oil.nvim",
+    lazy = false,
+    opts = {
+      view_options = { show_hidden = true },
+    },
+    keys = {
+      { "<leader>e", "<cmd>Oil<CR>", desc = "Open file browser" },
+    },
+  },
+  {
+    "folke/snacks.nvim",
+    priority = 1000,
+    lazy = false,
+    opts = {
+      picker = { enabled = true },
+      notifier = { enabled = true },
+      input = { enabled = true },
+    },
+    keys = {
+      { "<leader>f", function() require("snacks").picker.files() end, desc = "Find files" },
+      { "<leader>s", function() require("snacks").picker.grep() end, desc = "Search text" },
+      { "<leader>b", function() require("snacks").picker.buffers() end, desc = "Switch buffer" },
+    },
+  },
+}

reference/home/.config/nvim/lua/plugins/ui.lua

@@ -0,0 +1,55 @@
+return {
+  {
+    "gbprod/nord.nvim",
+    lazy = false,
+    priority = 1000,
+    opts = {
+      transparent = true,
+    },
+    config = function(_, opts)
+      require("nord").setup(opts)
+      vim.cmd.colorscheme("nord")
+    end,
+  },
+  {
+    "MeanderingProgrammer/render-markdown.nvim",
+    ft = { "markdown" },
+    dependencies = { "nvim-treesitter/nvim-treesitter" },
+    opts = {},
+  },
+  {
+    "folke/which-key.nvim",
+    lazy = false,
+    config = true,
+  },
+  {
+    "nvim-treesitter/nvim-treesitter",
+    branch = "master",
+    build = ":TSUpdate",
+    opts = {
+      ensure_installed = {
+        "markdown",
+        "markdown_inline",
+        "lua",
+        "bash",
+        "fish",
+        "rust",
+        "javascript",
+        "typescript",
+        "java",
+        "kotlin",
+        "c",
+        "cpp",
+        "html",
+        "css",
+        "python",
+      },
+      auto_install = false,
+      highlight = { enable = true },
+      indent = { enable = true },
+    },
+    config = function(_, opts)
+      require("nvim-treesitter.configs").setup(opts)
+    end,
+  },
+}

reference/home/.config/nvim/lua/vim_options.lua

@@ -0,0 +1,29 @@
+vim.g.mapleader = " "
+
+local opt = vim.opt
+
+-- Clipboard: use neovim's built-in OSC 52 provider, no external binary needed.
+vim.g.clipboard = "osc52"
+opt.clipboard = "unnamedplus"
+
+opt.number = true
+opt.relativenumber = true
+
+opt.shiftwidth = 2
+opt.tabstop = 2
+opt.expandtab = true
+
+opt.mouse = "a"
+
+opt.undofile = true
+
+opt.ignorecase = true
+opt.smartcase = true
+
+opt.splitright = true
+opt.splitbelow = true
+
+opt.wrap = false
+
+opt.scrolloff = 8
+opt.cursorline = true