FileNotFoundError: [Errno 2] No such file or directory: '/tmp/fletd-0.3.2-linux-amd64.tar.gz'

```shell
┌💁 jcleng @ 💻 nixos in 📁 ~
└❯ flatpak run org.openandroidinstaller.OpenAndroidInstaller
Traceback (most recent call last):
File "/usr/lib/python3.10/urllib/request.py", line 1348, in do_open
h.request(req.get_method(), req.selector, req.data, headers,
File "/usr/lib/python3.10/http/client.py", line 1282, in request
self._send_request(method, url, body, headers, encode_chunked)
File "/usr/lib/python3.10/http/client.py", line 1328, in _send_request
self.endheaders(body, encode_chunked=encode_chunked)
File "/usr/lib/python3.10/http/client.py", line 1277, in endheaders
self._send_output(message_body, encode_chunked=encode_chunked)
File "/usr/lib/python3.10/http/client.py", line 1037, in _send_output
self.send(msg)
File "/usr/lib/python3.10/http/client.py", line 975, in send
self.connect()
File "/usr/lib/python3.10/http/client.py", line 1447, in connect
super().connect()
File "/usr/lib/python3.10/http/client.py", line 941, in connect
self.sock = self._create_connection(
File "/usr/lib/python3.10/socket.py", line 845, in create_connection
raise err
File "/usr/lib/python3.10/socket.py", line 833, in create_connection
sock.connect(sa)
TimeoutError: [Errno 110] Connection timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/app/lib/python3.10/site-packages/flet/flet.py", line 492, in _download_fletd
urllib.request.urlretrieve(flet_url, temp_arch)
File "/usr/lib/python3.10/urllib/request.py", line 241, in urlretrieve
with contextlib.closing(urlopen(url, data)) as fp:
File "/usr/lib/python3.10/urllib/request.py", line 216, in urlopen
return opener.open(url, data, timeout)
File "/usr/lib/python3.10/urllib/request.py", line 525, in open
response = meth(req, response)
File "/usr/lib/python3.10/urllib/request.py", line 634, in http_response
response = self.parent.error(
File "/usr/lib/python3.10/urllib/request.py", line 557, in error
result = self._call_chain(*args)
File "/usr/lib/python3.10/urllib/request.py", line 496, in _call_chain
result = func(*args)
File "/usr/lib/python3.10/urllib/request.py", line 749, in http_error_302
return self.parent.open(new, timeout=req.timeout)
File "/usr/lib/python3.10/urllib/request.py", line 519, in open
response = self._open(req, data)
File "/usr/lib/python3.10/urllib/request.py", line 536, in _open
result = self._call_chain(self.handle_open, protocol, protocol +
File "/usr/lib/python3.10/urllib/request.py", line 496, in _call_chain
result = func(*args)
File "/usr/lib/python3.10/urllib/request.py", line 1391, in https_open
return self.do_open(http.client.HTTPSConnection, req,
File "/usr/lib/python3.10/urllib/request.py", line 1351, in do_open
raise URLError(err)
urllib.error.URLError:

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/app/lib/python3.10/site-packages/openandroidinstaller/openandroidinstaller.py", line 329, in
startup()
File "/app/lib/python3.10/site-packages/click/core.py", line 1130, in __call__
return self.main(*args, **kwargs)
File "/app/lib/python3.10/site-packages/click/core.py", line 1055, in main
rv = self.invoke(ctx)
File "/app/lib/python3.10/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/app/lib/python3.10/site-packages/click/core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "/app/lib/python3.10/site-packages/openandroidinstaller/openandroidinstaller.py", line 322, in startup
ft.app(
File "/app/lib/python3.10/site-packages/flet/flet.py", line 102, in app
conn = _connect_internal(
File "/app/lib/python3.10/site-packages/flet/flet.py", line 192, in _connect_internal
port = _start_flet_server(
File "/app/lib/python3.10/site-packages/flet/flet.py", line 292, in _start_flet_server
fletd_path = _download_fletd()
File "/app/lib/python3.10/site-packages/flet/flet.py", line 500, in _download_fletd
os.remove(temp_arch)
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/fletd-0.3.2-linux-amd64.tar.gz'

```

```
└❯ flatpak --version
Flatpak 1.14.0

OS: NixOS 22.11.3253.eac7da7b519 (Raccoon) x86_64
Kernel: 5.15.103
```

報告された NixOS 環境で `flatpak run org.openandroidinstaller.OpenAndroidInstaller` を使って、まず失敗を再現します。`/app/lib/python3.10/site-packages/flet/flet.py`、特に `_download_fletd()` と、`openandroidinstaller.py` のエントリーポイント `startup()` を確認します。ダウンロードのタイムアウトによって、二次的なファイル欠落エラーが発生しなければ完了です。

索引モデルが issue の本文から書いたものです。