feat: migrate from lazy.nvim to vim.pack

Replace lazy.nvim plugin manager with Neovim 0.12's native vim.pack API.
All plugin config files rewritten from lazy.nvim spec tables to imperative
require/setup format with explicit vim.keymap.set() calls.

Key changes:
- vim.pack.add() with ~53 plugins in init.lua
- blink.cmp/pairs/download pinned to version tags (vim.version.range)
- PackChanged autocmd for markdown-preview build hook
- Ordered requires: colorscheme → ui → treesitter → completion → lsp → rest
- Plugin setup guards (gitsigns, which-key, blink.cmp) handle deferred
  plugin/ file loading correctly

Net reduction: ~438 lines across 13 files.

1 files changed, 52 insertions, 72 deletions

diff --git a/home/.config/nvim/lua/plugins/ui.lua b/home/.config/nvim/lua/plugins/ui.lua
index f55ca45..50a2114 100644
--- a/home/.config/nvim/lua/plugins/ui.lua
+++ b/home/.config/nvim/lua/plugins/ui.lua
@@ -1,78 +1,58 @@
-return {
-  {
-    "ellisonleao/gruvbox.nvim",
-    priority = 1000,
-    config = function()
-      require("gruvbox").setup({})
-      vim.o.background = "dark"
-      vim.cmd([[colorscheme gruvbox]])
-    end,
-  },
-  {
-    "saghen/blink.indent",
-    --- @module 'blink.indent'
-    --- @type blink.indent.Config
-    opts = {
-      scope = {
-        highlights = {
-          "BlinkIndentOrange",
-          "BlinkIndentViolet",
-          "BlinkIndentBlue",
-          "BlinkIndentRed",
-          "BlinkIndentCyan",
-          "BlinkIndentYellow",
-          "BlinkIndentGreen",
-        },
-        underline = {
-          enabled = true,
-          highlights = {
-            "BlinkIndentOrangeUnderline",
-            "BlinkIndentVioletUnderline",
-            "BlinkIndentBlueUnderline",
-            "BlinkIndentRedUnderline",
-            "BlinkIndentCyanUnderline",
-            "BlinkIndentYellowUnderline",
-            "BlinkIndentGreenUnderline",
-          },
-        },
+-- blink.indent (gruvbox setup is in init.lua)
+require("blink.indent").setup({
+  scope = {
+    highlights = {
+      "BlinkIndentOrange",
+      "BlinkIndentViolet",
+      "BlinkIndentBlue",
+      "BlinkIndentRed",
+      "BlinkIndentCyan",
+      "BlinkIndentYellow",
+      "BlinkIndentGreen",
+    },
+    underline = {
+      enabled = true,
+      highlights = {
+        "BlinkIndentOrangeUnderline",
+        "BlinkIndentVioletUnderline",
+        "BlinkIndentBlueUnderline",
+        "BlinkIndentRedUnderline",
+        "BlinkIndentCyanUnderline",
+        "BlinkIndentYellowUnderline",
+        "BlinkIndentGreenUnderline",
       },
     },
   },
-  {
-    "nvim-lualine/lualine.nvim",
-    opts = {
-      options = {
-        icons_enabled = false,
-        theme = "gruvbox_dark",
-        component_separators = "",
-        section_separators = "|",
-        disabled_filetypes = {
-          winbar = {
-            "dap-view",
-            "dap-repl",
-            "dap-view-term",
-          },
-        },
-      },
-      sections = {
-        lualine_a = { "filetype", { "filename", path = 1 } },
-        lualine_b = { "%l/%L:%c:%o" },
-        lualine_c = { "diff" },
-        lualine_x = { "searchcount", "selectioncount" },
-        lualine_y = { "overseer", "copilot" },
-        lualine_z = { "diagnostics" },
-      },
-      inactive_sections = {
-        lualine_a = {},
-        lualine_b = {},
-        lualine_c = { "filename" },
-        lualine_x = {},
-        lualine_y = {},
-        lualine_z = {},
+})
+
+require("lualine").setup({
+  options = {
+    icons_enabled = false,
+    theme = "gruvbox_dark",
+    component_separators = "",
+    section_separators = "|",
+    disabled_filetypes = {
+      winbar = {
+        "dap-view",
+        "dap-repl",
+        "dap-view-term",
       },
     },
-    dependencies = {
-      "AndreM222/copilot-lualine",
-    },
   },
-}
+  sections = {
+    lualine_a = { "filetype", { "filename", path = 1 } },
+    lualine_b = { "%l/%L:%c:%o" },
+    lualine_c = { "diff" },
+    lualine_x = { "searchcount", "selectioncount" },
+    lualine_y = { "overseer", "copilot" },
+    lualine_z = { "diagnostics" },
+  },
+  inactive_sections = {
+    lualine_a = {},
+    lualine_b = {},
+    lualine_c = { "filename" },
+    lualine_x = {},
+    lualine_y = {},
+    lualine_z = {},
+  },
+})