docs(v3.5.0): update README for integrated mg_dotfiles and security improvements

- Integrated mg_dotfiles as regular directory (not submodule)
- Added .zshrc.local.example template for local configs without secrets
- Added mg_dotfiles/zsh/.zshrc.local to .gitignore to protect API keys
- Updated README to reflect mg_dotfiles integration and new structure
- Added nvim configuration directory with LazyVim setup

mg_dotfiles/nvim/lua/plugins/rip.lua

@@ -0,0 +1,22 @@
+-- This file contains the configuration for the nvim-rip-substitute plugin in Neovim.
+
+return {
+  -- Plugin: nvim-rip-substitute
+  -- URL: https://github.com/chrisgrieser/nvim-rip-substitute
+  -- Description: A Neovim plugin for performing substitutions with ripgrep.
+  "chrisgrieser/nvim-rip-substitute",
+
+  cmd = "RipSubstitute", -- Command to trigger the plugin
+
+  keys = {
+    {
+      -- Keybinding to perform a ripgrep substitution
+      "<leader>fs",
+      function()
+        require("rip-substitute").sub() -- Call the substitution function from the plugin
+      end,
+      mode = { "n", "x" }, -- Enable the keybinding in normal and visual modes
+      desc = " rip substitute", -- Description for the keybinding
+    },
+  },
+}