Initialize Neovim plugin structure

lua/jj_mini_diff/init.lua

@@ -0,0 +1,12 @@
+-- jj-mini.diff Neovim plugin
+
+local M = {}
+
+function M.setup(opts)
+  opts = opts or {}
+  -- TODO: Implement configuration options
+end
+
+-- TODO: Implement core logic for Git signs
+
+return M