Color Picker

Differences from upstream

• Exported as ColorPicker and ColorPickerPanel, like upstream. className and class are both accepted.
• icon is a Svelte snippet instead of a React component type.
• The format picker is a native select (no Select or Tooltip primitives are ported).
• The popover opens inline below the trigger instead of floating in a portal. It behaves like upstream's Popover otherwise: the trigger reports aria-expanded, focus moves into the panel on open, Escape, a click outside, or tabbing out closes it, and focus returns to the trigger.
• The copy button beside each channel row, focus-reselect, and opacity scrub-dragging are not ported. Copying a fully selected value field copies the CSS color, like upstream.
• In containers narrower than the panel (phones), the fields column wraps under the plane; upstream keeps one row and overflows.
• Accepts isDark and onIsDarkChange; it reflects isDark and never calls onIsDarkChange.
• Port addition: ColorPicker passes any other attributes (for example id, data-*, aria-*) through to its root element; upstream's ColorPickerProps accepts no extra attributes.