v10.82 - Dark-mode fixes + new color picker

Highlights

• Dark edit controls — text boxes (filter bars, FPS edits, hex inputs,
  every dialog edit) now have proper dark borders that highlight with the
  accent color on focus or hover, instead of the light Win11 sunken frame
  that fought with dark dialogs.
• Dark sliders — every trackbar (VXL Lighting sliders, audio player
  seek bar, video viewer scrubber, SHP player slider, the new color
  picker) renders with a dark channel and accent-colored thumb instead of
  the bright stock Win32 trackbar look.
• Brand-new color picker replaces the Windows color dialog at
  Theme > Alpha Color, the SHP custom side color swatch, and the VXL
  custom side color swatch. Three reasons:
  • Fully dark themed end to end, no more half-light dialog.
  • HSL sliders alongside RGB so you can pick by hue or lightness
    instead of three separate R/G/B values.
  • Hex input (3 or 6 digit, with or without #) for exact color
    entry.
  • All seven inputs (R, G, B, H, S, L, hex) are two-way bound: change
    one and the others update live; the preview swatch redraws on every
    keystroke.