feat: add Marshall CV-370 day/night toggle

[rueger-events-bot]

Summary

• Adds a Marshall CV-370 option in the NDI source panel with host/IP configuration.
• Adds a day/night toggle button that sends the CV-370 IR cut command used by the Marshall Companion module (ircut: 1 for daylight, ircut: 0 for night).
• Persists the CV-370 enablement, host, and last selected mode in project files.
• Adds a Qt unit test for CV-370 request URL generation.

Closes #1

Test Plan

• cmake -S . -B build-test -DBUILD_TESTING=ON with a local stub NDI SDK
• cmake --build build-test --target onpoint_tests --parallel
• ctest --test-dir build-test --output-on-failure

Note: a full Linux onpoint target build currently reaches an existing platform gap unrelated to this change: DnsSdBridge has macOS/Windows implementations, but no Linux implementation is linked by CMake.

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Recreated from upstream branch in hrueger/onpoint so GitHub Actions run in the repository context. Supersedes #2.