[neovim] replace neo-tree with snacks.nvim

Replace neo-tree.nvim with snacks.nvim for file explorer functionality and
remove several other plugins including:
- mini-animate
- mini-starter
- indent-blankline

The snacks.nvim plugin provides better file explorer, dashboard, indentation
guides, and other UI improvements in a more cohesive package.

Also removed the large file autocommand as snacks.nvim handles this with its
bigfile module.

.config/nvim/lua/plugins/neovim-project.lua

@@ -14,7 +14,7 @@ require("neovim-project").setup({
 	filetype_autocmd_timeout = 0,
 	session_manager_opts = {
 		autosave_ignore_filetypes = {
-			"neo-tree",
+			"snacks_picker_list",
 			"trouble",
 			"grug-far",
 			"copilot-chat",