Make changes to Photons screen from 1/16/25 design meeting

[arouinfar]

During today's design meeting, we discussed changes to the Coins and Photons screens. The Coins screen changes are tracked in #40 and #39.

Here is a summary of the changes to the Photons screen. See meeting notes for mockups.

• Average Polarization calculation: Only use math font for the expression to the left of the equals sign.
• Create AccordionBox for Probability readouts (default open)
• Photon Polarization Angle: Custom slider min/max labels should have units (°).
• Photon Polarization Angle: Set constrainValue to 5° increments.
• Photon Polarization Angle: Add angle representation to the diagram (following Trig Tour pattern of when to show/hide the arrowhead & theta)
• Photon Polarization Angle: Add angle readout next to the diagram
• Add linear gradient to the photon detectors.
• Histogram: Move V & H bars further away from the center
• Average Polarization Vector: Rescale/shorten vector display so +/-1 are centered on V & H.
• Average Polarization Vector: Move vector axis labels (+1, 0, -1) to the left side.
• Photons: Reduce the size of the central starburst.
• Photons: Do not reduce the opacity of the stroke around the photons. (Low-probability quantum photons will look empty.)