feat: setup plugin on require("flutter-tools").setup_project (#408)

Previously `FlutterRun` and other plugin commands were created only if
.dart or pubspec.yaml file were opened. This change will register plugin
commands on project config setup. So flutter app will be possible to
start without need to open dart file first.

lua/flutter-tools.lua

@@ -20,9 +20,6 @@ local command = function(name, callback, opts)
   api.nvim_create_user_command(name, callback, opts or {})
 end
 
----@param opts flutter.ProjectConfig
-function M.setup_project(opts) config.setup_project(opts) end
-
 local function setup_commands()
   -- Commands
   command("FlutterRun", function(data) commands.run_command(data.args) end, { nargs = "*" })
@@ -55,12 +52,17 @@ local function setup_commands()
   command("FlutterRename", function() require("flutter-tools.lsp.rename").rename() end)
 end
 
+local _setup_started = false
+
 ---Initialise various plugin modules
 local function start()
-  setup_commands()
-  if config.debugger.enabled then dap.setup(config) end
-  if config.widget_guides.enabled then guides.setup() end
-  if config.decorations then decorations.apply(config.decorations) end
+  if not _setup_started then
+    _setup_started = true
+    setup_commands()
+    if config.debugger.enabled then dap.setup(config) end
+    if config.widget_guides.enabled then guides.setup() end
+    if config.decorations then decorations.apply(config.decorations) end
+  end
 end
 
 local AUGROUP = api.nvim_create_augroup("FlutterToolsGroup", { clear = true })
@@ -113,6 +115,12 @@ local function setup_autocommands()
   })
 end
 
+---@param opts flutter.ProjectConfig
+function M.setup_project(opts)
+  config.setup_project(opts)
+  start()
+end
+
 ---Entry point for this plugin
 ---@param user_config table
 function M.setup(user_config)