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/copilot.lua

@@ -0,0 +1,20 @@
+return {
+  "zbirenbaum/copilot.lua",
+  optional = true,
+  opts = function()
+    require("copilot.api").status = require("copilot.status")
+    require("copilot.api").filetypes = {
+      filetypes = {
+        yaml = false,
+        markdown = false,
+        help = false,
+        gitcommit = false,
+        gitrebase = false,
+        hgcommit = false,
+        svn = false,
+        cvs = false,
+        ["."] = false,
+      },
+    }
+  end,
+}