Description:
I am building a custom Flet extension to bridge the telnyx_webrtc Flutter SDK. While the extension builds correctly for production targets, the local development runner (flet run) fails to recognize the control.

Environment:

• OS: Linux Mint

• Flet Version: 0.84.0

• Python: 3.13.1

• Project Structure:

TURAIT/
├── src/
│   ├── flet_webrtc/
│   │   ├── __init__.py
│   │   ├── flet_webrtc.py
│   │   └── flutter/ (Contains pubspec.yaml and Dart logic)
│   ├── views/
│   └── main.py
└── pyproject.toml

[tool.flet.dev_packages]
flet-webrtc = "src/flet_webrtc"

[tool.uv.sources]
flet-webrtc = { path = "src/flet_webrtc", editable = true }

Steps to Reproduce:

1. Define a class with @ft.control("FletWebrtc") in src/flet_webrtc/flet_webrtc.py.
2. Map the control in src/flet_webrtc/flutter/lib/main.dart following the extension template.
3. Attempt to use the control in main.py and run via flet run.
4. Result: Red "Unknown control: FletWebrtc" error in the UI.

Expected Behavior:
The desktop runner should be able to resolve local extensions defined in dev_packages during the development phase, or provide a clear mechanism for linking custom Dart code without a full build cycle.