fix(commands): prevent false positive "Flutter is already running!" s…

[zanadoman]

Fixed "Flutter is already running!" when retrying after device pick

What was happening

Sometimes flutter run exits with:

• No supported devices connected
• More than one device connected

When this happens, the plugin opens a small picker so you can pick a
device, then automatically retries the run with -d <your-device>.

The retry was failing with Flutter is already running!, even though
nothing was actually running.

Why

The plugin clears its internal runner state inside on_run_exit, but
it was doing it after showing the device picker:

local function on_run_exit(result, cli_args, opts, project_config, launch_config)
  local matched_error, msg = has_recoverable_error(result)
  if matched_error then
    ui.select({ ... })   -- opens picker (async, returns immediately)
  end
  shutdown()              -- runs too late
end

ui.select is asynchronous — it shows the picker, then waits for you
to pick. Your pick runs later in a callback, and that callback calls
M.run to retry. But shutdown() hadn't run yet, so the plugin still
thought a runner was active. The retry hit the is_running() guard
and bailed.

Fix

Move shutdown() to run before the picker:

local function on_run_exit(result, cli_args, opts, project_config, launch_config)
  shutdown()              -- clear state first
  local matched_error, msg = has_recoverable_error(result)
  if matched_error then
    ui.select({ ... })
  end
end

Now by the time the picker callback fires and the retry starts, the
old state is already gone and the retry can proceed.

Also tested it for two days at work, to make sure the fix works!

Thank you for your work!