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, 72 insertions, 79 deletions

diff --git a/home/.config/nvim/lua/plugins/session.lua b/home/.config/nvim/lua/plugins/session.lua
index 36759b0..a094727 100644
--- a/home/.config/nvim/lua/plugins/session.lua
+++ b/home/.config/nvim/lua/plugins/session.lua
@@ -1,84 +1,77 @@
-return {
-  {
-    "rmagatti/auto-session",
-    lazy = false,
-    opts = function()
-      local function get_cwd_as_name()
-        local dir = vim.fn.getcwd(0)
-        return dir:gsub("[^A-Za-z0-9]", "_")
+local function get_cwd_as_name()
+  local dir = vim.fn.getcwd(0)
+  return dir:gsub("[^A-Za-z0-9]", "_")
+end
+local overseer = require("overseer")
+
+require("auto-session").setup({
+  use_git_branch = true,
+  pre_save_cmds = {
+    function()
+      overseer.save_task_bundle(
+        get_cwd_as_name(),
+        nil,
+        { on_conflict = "overwrite" }
+      )
+    end,
+  },
+  pre_restore_cmds = {
+    function()
+      for _, task in ipairs(overseer.list_tasks({})) do
+        task:dispose(true)
       end
-      local overseer = require("overseer")
-      return {
-        use_git_branch = true,
-        pre_save_cmds = {
-          function()
-            overseer.save_task_bundle(
-              get_cwd_as_name(),
-              nil,
-              { on_conflict = "overwrite" }
-            )
-          end,
-        },
-        pre_restore_cmds = {
-          function()
-            for _, task in ipairs(overseer.list_tasks({})) do
-              task:dispose(true)
-            end
-          end,
-        },
-        post_restore_cmds = {
-          function()
-            overseer.load_task_bundle(
-              get_cwd_as_name(),
-              { ignore_missing = true, autostart = false }
-            )
-          end,
-        },
-        save_extra_data = function(_)
-          local ok, breakpoints = pcall(require, "dap.breakpoints")
-          if not ok or not breakpoints then
-            return
-          end
+    end,
+  },
+  post_restore_cmds = {
+    function()
+      overseer.load_task_bundle(
+        get_cwd_as_name(),
+        { ignore_missing = true, autostart = false }
+      )
+    end,
+  },
+  save_extra_data = function(_)
+    local ok, breakpoints = pcall(require, "dap.breakpoints")
+    if not ok or not breakpoints then
+      return
+    end
 
-          local bps = {}
-          local breakpoints_by_buf = breakpoints.get()
-          for buf, buf_bps in pairs(breakpoints_by_buf) do
-            bps[vim.api.nvim_buf_get_name(buf)] = buf_bps
-          end
-          if vim.tbl_isempty(bps) then
-            return
-          end
-          local extra_data = {
-            breakpoints = bps,
-          }
-          return vim.fn.json_encode(extra_data)
-        end,
+    local bps = {}
+    local breakpoints_by_buf = breakpoints.get()
+    for buf, buf_bps in pairs(breakpoints_by_buf) do
+      bps[vim.api.nvim_buf_get_name(buf)] = buf_bps
+    end
+    if vim.tbl_isempty(bps) then
+      return
+    end
+    local extra_data = {
+      breakpoints = bps,
+    }
+    return vim.fn.json_encode(extra_data)
+  end,
 
-        restore_extra_data = function(_, extra_data)
-          local json = vim.fn.json_decode(extra_data)
+  restore_extra_data = function(_, extra_data)
+    local json = vim.fn.json_decode(extra_data)
 
-          if json.breakpoints then
-            local ok, breakpoints = pcall(require, "dap.breakpoints")
+    if json.breakpoints then
+      local ok, breakpoints = pcall(require, "dap.breakpoints")
 
-            if not ok or not breakpoints then
-              return
-            end
-            vim.notify("restoring breakpoints")
-            for buf_name, buf_bps in pairs(json.breakpoints) do
-              for _, bp in pairs(buf_bps) do
-                local line = bp.line
-                local opts = {
-                  condition = bp.condition,
-                  log_message = bp.logMessage,
-                  hit_condition = bp.hitCondition,
-                }
-                breakpoints.set(opts, vim.fn.bufnr(buf_name), line)
-              end
-            end
-          end
-        end,
-        suppressed_dirs = { "~/", "/" },
-      }
-    end,
-  },
-}
+      if not ok or not breakpoints then
+        return
+      end
+      vim.notify("restoring breakpoints")
+      for buf_name, buf_bps in pairs(json.breakpoints) do
+        for _, bp in pairs(buf_bps) do
+          local line = bp.line
+          local opts = {
+            condition = bp.condition,
+            log_message = bp.logMessage,
+            hit_condition = bp.hitCondition,
+          }
+          breakpoints.set(opts, vim.fn.bufnr(buf_name), line)
+        end
+      end
+    end
+  end,
+  suppressed_dirs = { "~/", "/" },
+})