I've just tried running your example project, installed all pnpm and pip requirements (Python 3.11.5). The app seems to load fine but thet "Stop Sidecar" button bugs out, leading to the following error:

Sidecar stdout: [sidecar] Invalid command []. Try again.

Sidecar stdout: [sidecar] Invalid command []. Try again.

Sidecar stdout: [sidecar] Invalid command []. Try again.
[...]

Fatal Python error: _enter_buffered_busy: could not acquire lock for <_io.BufferedWriter name=''> at interpreter shutdown, possibly due to daemon threads

Python runtime state: finalizing (tstate=0x000000010250ab30)

Current thread 0x00000001f1c5fac0 (most recent call first):

Extension modules: pydantic.typing, pydantic.errors, pydantic.version, pydantic.utils, pydantic.class_validators, pydantic.config, pydantic.color, pydantic.datetime_parse, pydantic.validators, pydantic.networks, pydantic.types, pydantic.json, pydantic.error_wrappers, pydantic.fields, pydantic.parse, pydantic.schema, pydantic.main, pydantic.dataclasses, pydantic.annotated_types, pydantic.decorator, pydantic.env_settings, pydantic.tools, pydantic, httptools.parser.parser, httptools.parser.url_parser, websockets.speedups (total: 26)