The control-plane projection encoded risk with hue alone. The clear
green #3fb950 and the resolution red #ff7b72 differ by only 1.01:1 in
relative luminance, so a red-green color-blind operator saw the same
grey for "clear" and "steer now".
Risk now carries a second, non-color channel, matching the pattern
merged for the sibling airspace view in #3193:
- markers are drawn as a circle, square, or triangle per risk level
- the legend shows the matching glyph instead of color-only dots
- the Lanes panel prints the level name next to the percentage
- the canvas gets role="img" and a live aria-label describing counts
The clear green also moves to #2ea043 so it stays separable from the
resolution red by luminance (1.34:1) while keeping 5.73:1 against the
#0b0e14 background.
Adds tests/lib/control-plane-view-ui-a11y.test.js covering the roles,
the shapes, the legend, and the contrast ratios. The existing test
harness needed a setAttribute stub for the new aria-label update.
Co-Authored-By: CommandCodeBot <noreply@commandcode.ai>
