Port the boolab FX controls: localStorage-backed Density, Speed, and
Opacity sliders in the theme settings, shown when a canvas-background
theme is active (Density is matrix-rain-only). Speed is a multiplier over
each field's native base; values feed MatrixRain / NeonField live.
Override now uses the BooCode Classic warm tokens (orange/amber/rust on
warm near-black) instead of neon magenta/cyan/violet, with its neon-grid
field, glitch, scanlines, and bloom recoloured to match — a hotter,
glitchier Classic. Updates the NeonField canvas hues, the --bco-* effect
vars, and the picker preview anchors.
Add three opt-in dark themes (BooCode+, BooCode Classic, BooCode
Override) plus an in-place Ember polish, on a class-scoped effects
engine: matrix rain, a neon grid field, and frosted glass, all gated
by a localStorage "Animated background" toggle and prefers-reduced-
motion. Extend the server theme_id whitelist so the new ids persist,
and replace the Home landing wordmark with the stacked mascot +
wordmark banner.
