refactor: 重构Neovim配置结构并更新文档

- 调整配置文件组织方式，新增init.lua作为入口
- 更新lazy-lock.json同步插件版本
- 完善lua/目录下的插件和配置模块结构
- 修改README.md补充配置说明和使用指南

lua/config/lazy.lua

@@ -0,0 +1,15 @@
+local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
+if not (vim.uv or vim.loop).fs_stat(lazypath) then
+	local lazyrepo = "git@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)