Add HFJ-350M antenna calculator panel

[frankenstein91]

This PR introduces a dedicated calculator panel for the popular Comet HFJ-350M (Toy Box) portable antenna. It allows operators to quickly determine the correct antenna configuration without having to consult the manual during a field day.

Key Features:

• Dual Input: Supports both frequency (e.g., 7.1) and band names (e.g., 40m).
• Setup Guidance: Displays required coils, jumper terminals, and radial lengths based on the official manual.
• Precision Calculation: Calculates the exact telescopic whip length (in mm) based on the frequency deviation from the standard values.
• Visual Indicators: Features progress-bar style length displays for at-a-glance configuration.

Layout Integration:

• Modern Layout: Permanently integrated into the left sidebar below the propagation panel.
• Dockable Layout: Available as a new draggable panel ("HFJ-350M Calc" 📏) via the "+" menu.