feat(camera): add external camera streaming with tests and ci-cd

[charlesmadjeri]

External USB Camera Streaming with Client-Based Control

Overview

This PR adds refactored support for external USB webcam streaming with automatic load reduction when no clients are connected to the control panel.

Features

• External USB Webcam Support: Added ext_camera node with robust device detection using v4l2-ctl
• Service-Based Control: Implemented start/stop streaming services for manual and automatic control
• Client Count Monitoring: Automatic streaming control based on web panel client connections
• Optimized Streaming: GStreamer pipeline optimized for 1920x1080@30fps
• Unit Tests: Comprehensive pytest unit tests with mocking for hardware-independent testing
• CI/CD Pipeline: GitHub Actions workflow for automated linting and testing
• Code Coverage: Test coverage reporting with pytest-cov

Changes

• Renamed camera from mobius to ext_camera for consistency
• Moved to camera_stream_controller.py automatic client count monitoring
• Improved camera detection with vendor/product ID matching
• (re)Integrated camera launch into lucy.launch.py
• Updated system scripts for camera management
• Fixed all linting errors across Python and launch files

Related

• Frontend changes in web_control_panel repository

[Arcod7]

LGTM
This PR is too big for me to test everything in details but it seems right

[Arcod7]

I remember having a discussion about having a node "sensor interface" that would group everything but I don't think we made a doc for this. Does that remind you something?

[charlesmadjeri]

yep but actually the sensors are including the microphone and realsense that are handled in external node so it makes no sense to keep the camera publisher node named as sensor interface. But we can use sensor interface maybe to talk about the groups of nodes exposing sensors or maybe see if we can use a node to group several nodes (it it makes sense). But for now this change makes sense