Refactor plugin layout, add AI autocomplete and direnv, update docs

lua/plugins/direnv.lua

@@ -0,0 +1,7 @@
+-- direnv.vim - Auto-load project environment variables
+-- This enables project devShells to provide LSPs and tools automatically
+return {
+	"direnv/direnv.vim",
+	lazy = false, -- Must load early before LSP
+	priority = 90,
+}